Why Gwen Stefani Is in 'Panic Mode' Ahead of Upcoming Las Vegas Residency (Exclusive)

The 48-year-old singer told ET about her pre-show nerves at Moschino's star-studded runway show on Friday.

Gwen Stefani can't believe she's going to have a Las Vegas residency

The 48-year-old singer will kick off her 25-date residency, Gwen Stefani -- I'm Just a Girl, at the Zappos Theater at Planet Hollywood Resort and Casino on June 27, but right now, she's in "panic mode." 

ET spoke with Stefani at Moschino's Spring/Summer 19 Menswear and Women's Resort Collection runway show featuring FIJI Water at Los Angeles Equestrian Center on Friday, where she opened up about preparing for her next big career milestone. 

"I’m still in the panic mode of rehearsals. It feels like it’s not going to happen, but it will happen and it’s going to be one of those things that I look back on and go, 'That was a huge chapter of my life,'" she shared. "So, I’m very excited, I’m very honored.”

"I feel like it’s the kind of show that I’d never be able to do until this point in my life. [The show is] nostalgic, bringing people through the long journey I’ve been on with music and sharing that and exchanging the love I have with people," she added. "It’s really just that same journey again, but in a new Vegas-y way.”

While Stefani works out the kinks of her concert, she's already got her wardrobe picked out, including a look by Moschino's Jeremy Scott. The singer and mother of three told ET why it was important to take a break from rehearsals to support her friend. 

"We’re working together right now... I mean we’ve had rehearsals all day and I was like, 'I can’t [miss this].' You just want to support each other," she said. "I think it’s important to be around each other when we’re creating together. [The fashion show is] going to be really exciting. I would go to every fashion show in the world if I could and I never get to. So, this is a big night out for me.”

It was also a big night out for Stefani's three sons, Kingston, Zuma, and Apollo, who couldn't have had more fun as the Los Angeles Equestrian Center was transformed into a star-studded circus for the show. The venue featured a Ferris wheel, cotton candy machine and circus performers, and guests were treated to FIJI Water and popcorn at their seats. 

Stefani and her boys were seated with Eve, and next to Kris Jenner and Corey Gamble, who arrived hand in hand at the venue at around 7:30 p.m., and mingled with Scott before taking their seats. Also in attendance was Paris Jackson, who arrived about 30 minutes later with her friend, Caroline. Jackson quickly spotted Diddy's son, Quincy Combs, and made her way over to give him a hug. 

Jackson -- who met with Scott after the show -- later took her seat between Black Panther star Winston Duke and January Jones, as Jaime King, Emma Roberts, Brittany Snow, Aubrey Plaza, Maika Monroe, Sasha Lane and Isabela Moner made up the rest of their row.

The star sightings didn't end there, as Jimmy Iovine and Liberty Ross, as well as Red Hot Chili Peppers' Anthony Kiedis and Billy Idol were also at the show. Alessandra Ambrosio and Stella Maxwell walked the circular runway.

Celebs like Jackson and Ambrosio later hit up the after-party at the opening of Madame Siam's in Hollywood, where they were treated to carnival games behind a dance floor, as well as gifts from Moschino, like cell phone cases, scarves and sunglasses for winning the games. 

Missing from the festivities was Stefani's boyfriend, Blake Shelton. See more on the couple in the video below. 

Reporting by Angelique Jackson.