Kelly Rohrbach Lets It ALL Hang Out on the Beach ... Bae Watching Begins

Kelly Rohrbach is totally comfortable in that classic "Baywatch" one-piece, and just as comfortable out of it ... based on the nip slipping that went down during a photo shoot.

Kelly was posing Monday in Malibu for a Vogue spread that looked like a big promotion for the "Baywatch" movie -- and also for her amazing body.