The "Veronica Mars" cast is returning in full force for the movie ... TMZ has learned, Kristen Bell's co-star Percy Daggs III is 100% down for the reboot.

In case you didn't know, VMars fans broke film fundraising records yesterday ... generating more than $2 MILLION in just one day via Kickstarter to help resurrect the TV show as a movie. The project had existed in script form but failed to get the backing it needed ... until now.

Bell has already announced she's on board for the movie ... but now, her co-star Percy Daggs -- who played Wallace Fennel on the show -- tells TMZ, he's in too.

Daggs tells us, "Since I woke up yesterday it's been amazing to watch the VMars fans respond to this campaign and the opportunity to make this film."

He adds, "With [creator Rob Thomas] & Kristen's commitment to them and the series, I want to say I'm not surprised. But $2.7 million day one had to shock everybody a bit! ... I'd be honored to be a part of continuing this story for them onscreen."

IT'S REALLY HAPPENING!!!