Rapper Juicy J has been spilling the beans about the plans for Katy Perry's forthcoming Dark Horse video.

And the hip-hopper has told Billboard that he'll be starring in the promo, which he claims will be an epic production.

"It's a movie, man. It's a major motion picture," he said.

"I can't really tell you because it's definitely going to be a surprise, but I'll tell you this much right here: you've seen her other videos, this one's gonna be just as big.

"Everything she does is like grade A."

Dark Horse will be the third single lifted from her current album Prism.