The "Sing Your Face Off" contestant dishes to PEOPLE on what it took to pull off her performance of " Baby One More Time"

By Michele Corriston and Dahvi Shira
Updated June 06, 2014 07:30 AM

It’s Britney, b––––.

Well, not quite – but Lisa Rinna did a pretty good impression for ABC’s new reality competition show Sing Your Face Off.

The 50-year-old actress channeled her inner school girl on Saturday’s episode, impersonating Britney Spears and singing her 1999 smash ” Baby One More Time.”

Rocking the music video’s trademark pigtails, plaid skirt and belly-bearing collared shirt, Rinna gave a performance so convincing, you’d probably expect it during Spears’s Vegas show.

“It is a nonstop process for only five days, which is not a long time,” Rinna told PEOPLE on Thursday. “I knew I just had to throw myself into it and cram like I was cramming for finals, really. I just went for it and I knew I would have to go hard or go home. This is the kind of thing where you can’t just dip your toe into the water. You have to dive in or you will crash and burn.”

But Spears’s sensual moves aren’t for the inexperienced: Rinna thrust herself and judge Darrell Hammond onto the floor while attempting to sexily sit on the Saturday Night Live alumnus’s lap. Although she admits getting into character wasn’t necessarily a cinch.

“She’s only 16 or 17 in the video,” Rinna, who still had not watched her own performance at the time of this interview, explained. “She’s a young girl in a school girl uniform. That’s what was the most challenging. She dances really suggestively in her school girl uniform, so to get in that head space while being a woman in her late 40s at the time was really challenging.”

That said, the former soap star who deep down dreams of “being a rock star,” had the time of her life taking on such an iconic performance, despite its challenges.

“I had a blast doing it,” she said. “Britney is so specific and she’s an amazing performer, and when you really break someone down like Britney, she’s technical and does certain things with her voice that are very difficult. She’s a great dancer and it was really challenging to become her.”

Airing Saturdays at 9 p.m. ET, Sing Your Face Off finds Rinna, comedian Jon Lovitz, Disney Channel star China Anne McClain, rocker Sebastian Bach and NBA player Landry Fields imitating popular artists to see who can be the most convincing.

Watch Rinna as Spears below.

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