Millie Bobby Brown and Jake Bongiovi are displaying some major PDA. The couple was spotted kissing on July 4 while on a boat as part of their vacation in Sardinia, Italy.Bongiovi, the 20-year-old son of Jon Bon Jovi, sported a backwards baseball cap, sunglasses and swim trunks in the shot, while his star girlfriend, 18, paired a polka dot bikini with a baseball cap of her own.The pair sparked dating rumors last summer when Bongiovi shared a selfie of the duo cruising in the car.