Nick Jonas and Olivia Culpo are getting hot and heavy. The "First Time" singer, 20, and his girlfriend, 22, snuck in a kiss at the US Open in Queens, New York on Tuesday.

The couple's PDA while on a double date with Joe Jonas and Blanda Eggenschwiler was very passionate, according to E! Online. 

"Although they're a fairly new couple, it seems as though things between Nick and Olivia are getting pretty serious," wrote E!'s Bruna Nessif. "And we're not just talking the kissing department."

Jonas had a lot of fun not only kissing his brunette girlfriend, but enjoying the tennis matches. 

"US Open was so fun," Jonas wrote alongside an Instagram photo of the group. "Good people. Good tennis."

It appears that Jonas and the former Miss USA are getting very close lately. Right after rumors hit about their romance, the JoBro accompanied Culpo to her home state of Rhode Island for a weekend visit last month, reported E!. 

The crooner even reportedly had dinner with Culpo's parents and family at local eatery, Doughboys & Chowder House.

Jonas and Culpo's first public appearance, however, was at New York City's Ovest Pizzoteca on Aug. 1, according to Hollywood Life.

An eyewitness told HL that the twosome looked "really happy" together on their date even though they were not officially dating at the time. They met during the 2013 Miss USA Pageant in Las Vegas on June 16.

Think Jonas and Culpo make a cute couple? Tell us in the comments section below!