Who knew Fergie had the hots for former Guns N' Roses guitarist Slash?

The Black Eyed Peas lead singer is lending her voice, and incredible lady lumps, to his new video, Beautiful Dangerous.

In the video, Fergie, 35, is a crazed fan on a mission to get close to Slash ... and as you'll see by the end, it's a mission accomplished.

Josh Duhamel better watch out! His wife apparently knows how to use a knife in the bedroom as a method of persuasion. Wicked hot!