She says the girls have been talking about touring again, possibly in America!
"I feel very unprepared, in fact, it's crazy," Melanie C tells ET's Lauren Zima. "I had my first rehearsal yesterday and it was wild, because I have danced, you know, with the Spice Girls -- we do our little dance routines. I danced as a kid. I did ballet, and it's like, can you just forget everything you've ever learned? It's so, so different. And all the styles have such different techniques, so I like a challenge."
Noting that this year marks the 25th anniversary of the Spice Girls' first album, Spice, and their hit song, "Wannabe," Melanie C knows that she's going to have to bring the girl power.
"I really want to embrace that in the show, so it would be lovely and I'm keeping my fingers crossed that we get spice action," she shares.
Could this "spice action" mean we'll see some of the Spice Girls in the ballroom?
"It'd be rude not to, right?" she jokes.
The group performed on the show back in 2007 when Melanie C's Spice Girls bandmate, Mel B, competed on season 5, coming in second place at the time.
Calling the experience "wonderful," the pop star says her bandmate gave her some sage advice.
"She said, just enjoy it, lap it up," she shares.
Will the group reunite to perform again on the show?
"I really hope so. I think that could really... should we manifest that that is gonna happen?" she jokes.
Melanie C says she talked to "all the girls" about her decision to take part in the competition and got nothing but love and support from them.
"They're all super excited for me, and they're kinda, like, 'You've gotta win!'" she says. "That's a bit of pressure, so I was like, 'I'll do my best.'"
She says the Sporty Spice title often gives fans and friends an unrealistic view of her abilities.
"'Cause I'm the sporty one, they always think, 'Yeah, she's gonna get gold, but you know, there's more sporty people in this show than me, like, super sporty who really have won gold," she says of the cast, which includes Olympian Suni Lee. "But I'm gonna give it my best shot."
She also, of course, has a lot of hits to choose from on the dance floor.
"We have beautiful ballads," she says of the Spice Girls' catalogue. "You could do something really lyrical and beautiful like '2 Become 1,' 'Forever,' but then we've got the fun stuff -- 'Spice Up Your Life,' 'Wannabe,' so there's quite a lot to pick from."
As for the group's future plans following their sold-out 2019 U.K. tour, Melanie C says they're ready to get on the road again.
"We are talking right now. We wanna get out there. We wanna do shows again," she says. "We toured the U.K. in 2019, then, of course, the world's gone crazy, so when everything's safe again, we wanna get back out there, so America's kind of top of our list."
Dancing With the Stars season 30 premieres Sept. 20 at 8 p.m. on ABC.