Nikki Bilderback -- who played Whitney in the hit 2000 movie -- tells TMZ ... she'd absolutely do a sequel provided it comes with a good script and the other ladies sign on.

NB says the movie needs to hold its own because so many generations of fans love the film. She says she gets fans from 12 to 50 telling her how much they love the flick ... and she doesn't want to let them down.

Nikki's got connections with the original cast too, adding she still regularly chats with Clare Kramer -- who played her best friend Courtney in the movie -- and used to hang with Gabrielle Union all the time. So, if the studio needs someone to reach out, sounds like Nikki's their lady!

As for what she thinks her character is up to ... Nikki says she thinks Whitney's still best friends with Courtney and imagines a sequel centered on a high school reunion -- pretty apt given the movie itself would serve as a major reunion.

Like we mentioned, Dunst is also talking up the idea ... telling Entertainment Tonight she'd agree to it so long as it's not embarrassing -- a pretty fair request, we gotta say.

While the studio's made several 'Bring It On' sequels over the years, they didn't feature any of the original cast ... so, a reunion would constitute the first true sequel.