Credit: Dave M. Benett/Getty Images

What's up with Brad Pitt's gnarly-looking facial fuzz?

"It's boredom. No other reason than that," the actor, 46, tells Britain's Sun.

On Monday, a solo Pitt, 46, was in London to promote the action-thriller Kick-Ass (out Apr. 14), which he helped produce for director Matthew Vaughn (husband of pregnant supermodel Claudia Schiffer).

He has since returned to Venice, where his self-described "soul mate" Angelina Jolie is shooting The Tourist with Johnny Depp.

Asked how his time has been there, he told "Lovely!"

On Tuesday, Pitt and Jolie, 34, showed off a rare glimpse of their 20-month-old twins Vivienne and Knox while relaxing on the private balcony of the 15th century palazzo they're renting.