The stars spoke with ET on the carpet at the premiere of 'Cruel Summer' season 2 at the Grace E. Simons Lodge in L.A. on Wednesday.
Both stars -- who played sisters on the popular family drama series -- walked the carpet at the season 2 premiere of Cruel Summer at the Grace E. Simons Lodge in Los Angeles, and spoke with ET's Cassie DiLaura about their friendship.
"It's literally like a high school reunion for all of us," Mitchell marveled. "I mean, it's amazing."
Among those on the carpet was former NSYNC star Lance Bass -- who also made his TV acting debut on an episode of 7th Heaven, making the reunion even more unique.
"I can't wait to see Lance tonight," Biel told ET of her former co-star and her husband Justin Timberlake's former bandmate. "It's a lot. There's a lot of friends from the '90s who are here tonight."
"It's the thing in the zeitgeist right now. People are loving the show again, and it's amazing," Bass told ET as he walked the carpet with husband Michael Turchin.
Looking back on his memories of his brief but impactful time on the show, Bass recalled, "It was my first acting job ever, so I didn't know what the hell I was doing. But they were so great to me, and they held my hand I remember thinking how great all the other actors were... It was one of the best lessons of my life."
Meanwhile, Mitchell was overwhelmed with excitement for Biel -- who serves as an executive producer on Cruel Summer.
"Jessie and I see each other often, cause obviously, like, she's my bestie, she's my ride or die. But it's always fun to be able to come out and support her and cheer her on," she shared. "I'm so proud of everything that she's done and this is so amazing."
As for Cruel Summer, the popular anthology drama series' first season was set in the mid-1990s, while the second season tells a whole new story about an intense teenage friendship set in the early 2000s.
The show taps into a sense of nostalgia that has really spoken to viewers, and Biel feels she understands the draw to the past.
"I think it's because times [seemed] simpler. I mean, as amazing as technology is, and all the incredible advancements that are happening -- I get it, it's amazing. But I missed the simple days when, you know, you just play outside in your cul-de-sac until the streetlights went on and you ran home," she shared. "I'm just kind of an old school dinosaur. A person that likes the simpler times and I wonder if other people get that too. I don't know."
Season 2 of Cruel Summer premieres June 5 on Freeform.