Credit: Steve Granitz/

Don't call her Mrs. Depp!

Johnny Depp, 47, tells Extra the reason he hasn't wed gal pal of 12 years Vanessa Paradis is because "I'd be so scared of ruining her last name. She's got such a good last name."

The three-time Oscar nominee, whose thriller The Tourist with Angelina Jolie hits theaters next Friday, adds he already feels as if he's wed to the French model/actress, 37.

"I never found myself needing that piece of paper," he says. "Marriage is really from soul to soul, heart to heart. You don't need somebody to say, okay you're married."

That being said, Depp admits he'd be willing to take the plunge, "if Vanessa wanted to get hitched."

For now, the twosome are looking forward to spending the holidays relaxing with their kids Lily-Rose, 11, and Jack, 8. 

On the agenda: "Sleeping, sleeping and playing with a lot of toys with my son," says the actor. "Hanging out with the kiddies."