Last week we told you about Fabio's new gig as the Old Spice Guy. But it seems he's not content just to replace Isaiah Mustafa -- now he's challenged his predecessor to a duel as well.

Mustafa accepted, so it's ON, people!

What exactly "it" is remains to be seen, but the Old Spice YouTube channel promises to reveal all at duel time -- Tuesday, July 26 at noon eastern.

[via Buzzfeed]