On the Fox singing competition series' season 11 premiere March 6, host Nick ... out it wasn't actually a mystery celeb competing for The Masked Singer title—it was Cannon's BFF and longtime ...

Once Book popped out of his pages, Hart, 44, appeared. "I got you Nick!" the Lift star declared. A completely shocked Cannon, 43, asked Hart for an explanation. "This is a prank!" Hart continued.