The couple that hits the lanes together, stays together!

Justin Bieber and Selena Gomez are still going strong, and they definitely had the look of love at JB's childhood pal Ryan Butler's birthday party at Lucky Strike in Hollywood on Sunday. The pair were allegedly kissing and canoodling in between knocking down the pins!

"Justin rented out Lucky Strike's Luxe room for the celebration. Additionally, he was seen kissing and flirting with his on-and-off again girlfriend, Selena Gomez," a source told E! News.

Although the group is too young to drink alcohol, they still took advantage of the venue's service and chowed down! "The group, of about 12 people in all, enjoyed some of Lucky Strike's Esteban's nacho's grande, cheeseburgers and wings. Specifically, Justin was seen eating the mac and cheese bites," the source added.

Earlier in the weekend, the lovebirds were spotted in Sin City to take in The Biebs' pal Floyd Mayweather's boxing match. They aren't trying to hide their on-again romance any more!