Queen Letizia is stunning in plaid pants as she arrives

Queen Letizia is stunning in plaid pants as she arrives at her sister-in-law Infanta Elena's 60th birthday celebrations (and even disgraced former King Juan Carlos showed up).

Queen Letizia cut an elegant figure at her sister-in-law's 60th birthday celebrations in Madrid today.

The 51-year-old queen appeared to be in high spirits as she arrived with King Felipe at the exclusive Pabú restaurant in the country's capital.

For the family reunion, the mother of two chose eye-catching green and blue checked trousers.

In the picture, the stylish royal wore a thin leather belt with delicate silver hardware that contrasted perfectly with the trouser buttons.

Letizia let her statement pants take center stage and paired them with a simple black crew neck sweater and chunky black shoes.

Pictured: King Felipe and Queen Letizia appeared in high spirits today as they arrived at the Pabú restaurant in Madrid

Pictured: King Felipe and Queen Letizia appeared in high spirits today as they arrived at the Pabú restaurant in Madrid

The queen wore her glossy brown hair straight and wore some dangling emerald earrings in the picture, which highlighted the green of her checked pants.

Anticipating that it would be colder, the Queen was also seen with a leather jacket in her hand, which she had taken off.

King Felipe – her husband of 19 years – looked equally dapper in a dark gray suit.

The king paired his suit with a light blue shirt, a red patterned tie and maroon patent leather shoes.

The couple were seen happily chatting to staff as they arrived, before later peeking through the door to wave to royal fans.

Meanwhile, Felipe's father Juan Carlos was also seen arriving at the restaurant for his daughter's birthday party shortly afterwards.

The disgraced king has spent the last few years living in self-imposed exile in Abu Dhabi after abdicating in June 2014 following a corruption scandal.

For the occasion, the 85-year-old former king wore a dark blue suit, a white shirt and a patterned tie.

Letizia left the restaurant after entering to wave to royal fans who had been waiting for her arrival

Letizia left the restaurant after entering to wave to royal fans who had been waiting for her arrival

Anticipating that it would be colder, the Queen was also seen with a leather jacket in her hand, which she had taken off

Anticipating that it would be colder, the Queen was also seen with a leather jacket in her hand, which she had taken off

Felipe's father, Juan Carlos, was also seen shortly afterwards arriving at the restaurant for his daughter's birthday party

Felipe's father, Juan Carlos, was also seen shortly afterwards arriving at the restaurant for his daughter's birthday party

The royal couple waved during their outing as they attended Elena de Borbón's 60th birthday

The royal couple waved during their outing as they attended Elena de Borbón's 60th birthday

King Felipe and his wife Letizia, both pictured in style in Madrid today, attended the birthday celebrations

King Felipe and his wife Letizia, both pictured in style in Madrid today, attended the birthday celebrations

The royal couple wore sophisticated, stylish ensembles to today's birthday bash in Madrid

The royal couple wore sophisticated, stylish ensembles to today's birthday bash in Madrid

The couple smiled as they enjoyed today's celebrations for Elena de Borbon's 60th birthday

The couple smiled as they enjoyed today's celebrations for Elena de Borbon's 60th birthday

The King and Queen of Spain were in high spirits as they took part in today's celebrations

The King and Queen of Spain were in high spirits as they took part in today's celebrations

King Emeritus Juan Carlos I exchanged warm greetings with guests at the birthday party in Madrid.  In the picture with the birthday child

King Emeritus Juan Carlos I exchanged warm greetings with guests at the birthday party in Madrid. In the picture with the birthday child

The birthday boy's father was in high spirits as he attended today's celebrations in Madrid

The birthday boy's father was in high spirits as he attended today's celebrations in Madrid

The King was cheerful as he chatted with others at birthday celebrations in Madrid today

The King was cheerful as he chatted with others at birthday celebrations in Madrid today

The beaming Infanta Elena drove to the restaurant in the car and was happy to receive a bouquet of flowers from photographers

The beaming Infanta Elena drove to the restaurant in the car and was happy to receive a bouquet of flowers from photographers

Dozens were present at today's birthday party.  In the picture: Royals in the restaurant in Madrid

Dozens were present at today's birthday party. In the picture: Royals in the restaurant in Madrid

Felipe's mother, Queen Emeritus Sofia, appeared in a chic patterned blue blazer.  Meanwhile, her daughter Infanta Cristina chose a black short jacket

Felipe's mother, Queen Emeritus Sofia, appeared in a chic patterned blue blazer. Meanwhile, her daughter Infanta Cristina chose a black short jacket

Sofia beamed as she attended her daughter's birthday party.  Pictured with her youngest daughter

Sofia beamed as she attended her daughter's birthday party. Pictured with her youngest daughter

The royals stepped out in matching deep blue ensembles as they enjoyed today's birthday celebrations

The royals stepped out in matching deep blue ensembles as they enjoyed today's birthday celebrations

Sofia and Cristina wore matching grins as they appeared at today's birthday bash

Sofia and Cristina wore matching grins as they appeared at today's birthday bash

Pictured: Queen Emeritus Sofia and Irene of Greece attended today's birthday celebration

Pictured: Queen Emeritus Sofia and Irene of Greece attended today's birthday celebration

Sofia, Cristina and Irene were among the famous faces at today's 60th birthday gathering in Madrid

Sofia, Cristina and Irene were among the famous faces at today's 60th birthday gathering in Madrid

The beaming Infanta Elena drove to the restaurant in the car and was happy to receive a bouquet of flowers from photographers.

The queen – who also holds the title Duchess of Lugo – has managed to keep a relatively low profile despite being the king's sister.

Elena shares her daughter Victoria de Marichalar y Borbón and her son Felipe with her ex-husband Jaime de Marichalar.

The couple married in 1995 before divorcing in 2009. At the time, the couple issued a statement saying they “maintain a fluid dialogue on all matters affecting the common interest of their children.”

Irene Urdangarin - whose mother is the Spanish Infanta Cristina - chose a very trendy outfit for her birthday

Irene Urdangarin – whose mother is the Spanish Infanta Cristina – chose a very trendy outfit for her birthday

The 18-year-old attended her family's celebrations and was pictured at the restaurant in Madrid

The 18-year-old attended her family's celebrations and was pictured at the restaurant in Madrid

Infanta Cristina's daughter Irene opted for a stylish outfit with a maxi skirt and leather jacket

Infanta Cristina's daughter Irene opted for a stylish outfit with a maxi skirt and leather jacket

Pictured: Irene and her brother Juan were both present at their aunt's birthday party

Pictured: Irene and her brother Juan were both present at their aunt's birthday party

Irene and Juan present their best fashion for today's event and look stylish and chic for their birthday

Irene and Juan present their best fashion for today's event and look stylish and chic for their birthday

Pictured: Margarita de Borbon and Carlos Zurita in the restaurant during the celebrations today

Pictured: Margarita de Borbon and Carlos Zurita in the restaurant during the celebrations today

Margarita is the younger sister of King Juan Carlos and therefore Felipe's aunt.  Pictured at today's birthday

Margarita is the younger sister of King Juan Carlos and therefore Felipe's aunt. Pictured at today's birthday

Simoneta Gomez Acebo - in a chic, neutral-toned ensemble - was also in attendance today

Simoneta Gomez Acebo – in a chic, neutral-toned ensemble – was also in attendance today

Royal mother-of-two Infanta Elena celebrated her 60th birthday with an intimate family dinner today

Royal mother-of-two Infanta Elena celebrated her 60th birthday with an intimate family dinner today

KingCharles, Infanta Elena, Queen Sophia, Prince Harry on the knee of King Juan Carlos, Prince Harry, Princess Diana, Infanta Cristina, King Felipe, pictured in Mallorca in 1988

KingCharles, Infanta Elena, Queen Sophia, Prince Harry on the knee of King Juan Carlos, Prince Harry, Princess Diana, Infanta Cristina, King Felipe, pictured in Mallorca in 1988

King Felipe's sister Infanta Elena with her ex-husband Jaime De Marichalar at Queen Letizia's wedding in 2004. The couple separated in 2009

King Felipe's sister Infanta Elena with her ex-husband Jaime De Marichalar at Queen Letizia's wedding in 2004. The couple separated in 2009

She has appeared on the covers of magazines such as Elle Spain and was dubbed the latest

21-year-old Victoria de Marichalar y Borbón (pictured) has taken Instagram by storm as she documents her stylish lifestyle – including trips to Greece, Florence in Italy and the French capital for Paris Fashion Week

King Felipe VI's sister, Infanta Cristina of Spain, 58, left, pictured with her 25-year-old husband Iñaki Urdangarin, 55, before their separation in 2022 (pictured together in 2019 in Vitoria).  The couple have four children together, but their marriage collapsed after he was sentenced to five years in prison for financial crimes and charged with fraud in 2018

King Felipe VI's sister, Infanta Cristina of Spain, 58, left, pictured with her 25-year-old husband Iñaki Urdangarin, 55, before their separation in 2022 (pictured together in 2019 in Vitoria). The couple have four children together, but their marriage collapsed after he was sentenced to five years in prison for financial crimes and charged with fraud in 2018

It is unknown whether Felipe and Elena's sister Infanta Cristina will attend today's celebrations – after she found herself at the center of one of the Spanish monarchies' biggest scandals.

In 2018, the king's former brother-in-law was jailed for financial crimes.

Businessman and retired handball player Iñaki Urdangarin, 54, was sentenced to five years in prison in 2018 for embezzling and money laundering more than £4.5 million through his charity, the Noos Institute.

Urdangarin married Infanta Cristina in 1997 and the couple have four children together, all in their late teens or early twenties: Juan, Pablo, Miguel and Irene.