Gwyneth Paltrow Caught Playing Kissy Face With Mark Ruffalo! (PHOTOS)

Why is Gwyneth Paltrow locking lips with Mark Ruffalo if she's married to Chris Martin?

Will Chris Martin send Jay-Z and the Roc Boys after Mark?!

PHOTOS: Gwyneth Paltrow Locks Lips With Mark Ruffalo

Probably not, because these two are just filming a movie called Thanks For Sharing.

Gwyneth was spotted in Central Park, NY doing her thing running, riding a bike and stretching while wearing spandex, when she bumped into Mark Ruffalo. 

PHOTOS: Gwyneth Paltrow Is Red Carpet Cute

The kiss must have done something to Gwyneth, because it took her back her days as a young girl.

She tweeted:

"Shooting in sunny central park. Reminds me of my youth. Whatever happened to bartles and jaymes? Could rock one of those things."

Gwyneth sure did look like she was embracing her youthful side, as she cuddled and kissed all over Mark!

Could you let your significant other kiss someone else for work? 

Photos

Gwyneth Paltrow And Mark Ruffalo Kiss While Filming "Thanks For Sharing" (PHOTOS)