Hilary Duff was one of thousands in attendance at the When We Were Young music festival in Las Vegas this past weekend!

The 36-year-old actress joined the fun at the concert event to cheer on her husband Matthew Koma, who performed on stage at the fest.

Matthew actually played guitar and sang backing vocals for Hilary‘s ex boyfriend Joel Madden‘s band Good Charlotte!

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Hilary shared photos and videos on her Instagram story from her time at the event, from the side of the stage watching on as the band played. She was seen hanging out with her longtime best friend Alanna Masterson, Matthew‘s BFF Christopher Mintz-Plasse, and even Joel‘s wife Nicole Richie.

“played in my buddies’ band @goodcharlotteband this weekend, drank Jared Leto’s coconut water, & played A Milli with Lil Wayne, 10/10,” Matthew captioned a post of photos and videos from the weekend.

Joel commented, “You are the heart and soul of GC 😍,” while his brother Benji wrote, “We decided we Really can’t play with out you now 😭😭😭❤️❤️❤️❤️”

If you didn’t know, Hilary and Matthew, and Joel and Nicole are all good friends, and even neighbors!

Earlier this year, the How I Met Your Father star opened up about her current friendship with Joel, who she dated from 2004-2006.