Sofia Richie and her sister Nicole join Cameron Diaz as

Sofia Richie and her sister Nicole join Cameron Diaz as the star-studded opening act for Benji and Joel Madden’s band Good Charlotte at the When We Were Young Festival

Sofia Richie and her husband Elliot Grainge, along with sister Nicole Richie and Cameron Diaz, supported their husbands Joel Madden and Benji Madden at the When We Were Young Festival in Las Vegas.

Sofia’s, 25, brother-in-law Joel (and Cameron’s husband Benji) is part of the band Good Charlotte, which reunited to play at the music festival, which celebrates music from the 1990s and 2000s.

The influencer, who attended the Madden brothers’ streamer launch with Nicole and Cameron, looked chic in a cream sleeveless silk top and wide-leg black pleated trousers.

She paired the elevated look with pointy black shoes and wayfarer-style sunglasses.

Her blonde hair was parted in the middle and flowed down her back as she sipped on a can of Liquid Death water.

Supportive brother-in-law: Sofia Richie and her husband Elliot Grainge were in attendance to cheer on Joel Madden and Benji Madden at the When We Were Young Festival in Las Vegas

Supportive brother-in-law: Sofia Richie and her husband Elliot Grainge were in attendance to cheer on Joel Madden and Benji Madden at the When We Were Young Festival in Las Vegas

Bond: Cameron Diaz (left) and Nicole Richie were also in attendance to support her husband's band Good Charlotte

Bond: Cameron Diaz (left) and Nicole Richie were also in attendance to support her husband’s band Good Charlotte

Nicole, 42, has been dating Joel Madden since 2006 and married since 2010.

They share daughter Harlow, 15, and son Sparrow, 14.

The Simple Life alum kept her outfit simple by donning a comfortable black tank dress.

Cameron, 51, married Joel’s twin brother Benji in 2020 and the couple welcomed their daughter Raddux via surrogate in 2020.

The Something About Mary actress wore a black tank top with thin straps and light wash jeans as she held a cup of lemonade in the VIP section of the festival.

Joel’s ex-girlfriend Hilary Duff, 36, also attended the festival with her husband Matthew Koma.

The Younger alum dated Joel from 2004 to 2006, getting together when she was 16 and he was 25.

The Lizzie McGuire star looked comfortable in a pair of tight black trousers and a white t-shirt.

The rock star's other wife: Cameron, 51, married Joel's twin brother Benji in 2020 and the couple welcomed their daughter Raddix via surrogate in 2020.  The Something About Mary actress wore a black tank top with thin straps and a pair of light washed jeans as she held a cup of lemonade in the VIP section of the festival

The rock star’s other wife: Cameron, 51, married Joel’s twin brother Benji in 2020 and the couple welcomed their daughter Raddix via surrogate in 2020. The Something About Mary actress wore a black tank top with thin straps and a pair of light washed jeans as she held a cup of lemonade in the VIP section of the festival

Band back together: The When We Were Young Festival was Good Charlotte's first performance since 2019

Band back together: The When We Were Young Festival was Good Charlotte’s first performance since 2019

The ex-girlfriend: Joel's ex-girlfriend Hilary Duff, 36, also attended the festival with her husband Matthew Koma

The ex-girlfriend: Joel’s ex-girlfriend Hilary Duff, 36, also attended the festival with her husband Matthew Koma

Hilary slipped on a pair of black Mary Jane-style flats and carried a white handbag over one shoulder.

Good Charlotte’s performance at the festival on Saturday was their first performance since May 2019.

The band, formed in Maryland in 1996, played a nine-song setlist.

The setlist included hits like “Little Things,” “Anthem” and “Lifestyles of the Rich & Famous.”