ET has learned that the dancer and actress has been paired up with 'DWTS' pro, Jenna Johnson.
Siwa first spilled the news on E!'s Daily Pop Thursday when asked if her girlfriend, Kylie Prew, was jealous of her dance partner. The J-Team star said Prew told her, "Tell Jenna, she needs to leave room for Jesus."
"When I read the email it was like, 'Would JoJo prefer to dance with a girl or with a boy?' And I was like, 'Wait, that's an option? Let's absolutely do it!'" Siwa recalled. "It was a like, 'Whoa, I'm changing the future' [moment], because I have such a kid demographic. It's making it acceptable, and I love that and I'm so proud of that."
It's a pairing Johnson is really proud of too. The DWTS pro told ET earlier this week, that Siwa is the perfect person to make this historic change on the long-running show.
"I think it's time, and I think for Dancing With the Stars to be the first one to do this is incredible," Johnson shared. "I think JoJo is the perfect person to represent that, and I'm really excited to see what she does."
Before starting rehearsals Tuesday, Siwa told ET that she was anxious to find out which female pro she'd be paired up with this season, and included Johnson in her list of favorites.
"I actually start rehearsals tomorrow!" she excitedly revealed Monday, telling ET that her "three favorite" pros are Johnson, Britt Stewart and Lindsay Arnold. "I meet [my partner] tomorrow."
Siwa added that she is a bit nervous about having a background in dance, as it could either help her or hurt her with DWTS fans, and judges Derek Hough, Bruno Tonioli, Carrie Ann Inaba and Len Goodman.
"I'm not gonna hide that I'm a dancer. I was a dancer my whole life," she said. "Am I very out of practice? Absolutely. I perform all the time, but it's different, you know? I don't have to strengthen my legs, and ballroom is different. I've never taken ballroom."
"It's gonna help me in a way, but it also is a disadvantage," she continued. "Because I guarantee you the judges are one hundred million percent gonna judge me harder than they do everybody else."
Find out who Siwa hits the dance floor with when Dancing With the Stars returns to ABC for its 30th season on Monday, Sept. 20.