Justin posted a romantic picture of him smooching his Disney star girlfriend, who turned 19 on Friday, via his Instagram account.
In the snap he kisses her tenderly on the cheek in what appears to be a backseat of a car. Selena is seen closing her eyes and beaming in the black and white picture, captioned 'Happy Birthday baby.'
The fact that Justin posted the snap of on the public social networking application, which is seen by thousands of his fans, is just another indication as to how much he cares for his older girlfriend.
Selena had a ball as she was treated by Justin to a rather large shopping trip at the 'happiest place on earth', during her special day.
The couple browsed one of Disneyland's many merchandise stores, picking up an array of items, before spending several hours in the theme park itself. Earlier in the day, Justin hinted something special was on the card for his girl, via his Twitter.
'Happy Birthday @SelenaGomez gonna be a special day' he wrote.
And aside from their special trip to the theme park on Friday, the pint-sized pop star hardly left his lady love's side all weekend. The teen sensation also joined Selena on-stage last night, as she kicked off her tour in Costa Mesta, California.
The stunning brunette performed her hits in a dark pink sequinned frock and pair of flats and was surprised when Justin jumped up midway through the performance.
After giving his girlfriend a big bear hug, he then proceeded to sing an acoustic version of Justin Timberlake's hit song 'Cry Me A River' and also performed his own hit, 'Favourite Girl'.
Following the show, proud Justin later tweeted to his fans: 'Had a #greatnight and surprised the people. felt good to be on stage. nothing is changing that. #REAL. @selenagomez u did great tonight. proud of u.'
Earlier this week, Selena this week laughed off speculation that pregnancy was actually the cause of her illness last month. The former Disney star was hospitalised and treated for malnutrition after complaining of headaches and nausea. However, there were whispers her health scare was pregnancy-related.
Talking about the claims, she told Now magazine: 'I laughed. There is nothing you can do, you just have to blow them off. She said that the real cause was her poor diet.
'I wasn't really healthy. I was low in iron. I was dehydrated. I had actually got back from vacation, so I wasn't overworking.
'I'm probably not the healthiest eater.'