The placement of the "No Smoking" sticker is pretty perfect...

On Saturday Kristen Stewart was snapped riding shotgun in a car on the set of her new film, Camp X-Ray, and it looks like she won't be lighting up in this vehicle!

The 23-year-old starlet may be quite the little chain smoker, but her former beau Rob Pattinson reportedly ditched the dirty habit after the two split this spring. "Rob has finally quit smoking for good. And he feels and looks healthier than ever. Working out has helped him tremendously with regard to quitting smoking," a source told HollywoodLife. "The two just don't go hand-in-hand. Rob is now addicted to exercising and feeling good. Rob has been training diligently with famed celebrity fitness instructor Harley Pasternak. He's determined to get into the best shape of his life."

Hopefully we'll get a peek at his hot bod sooner or later! You know K. Stew is kicking herself over this...