Things are heating up!
"They're pretty much inseparable. They're together all the time, unless she has a Miss Universe event," the source explained.
The couple's fairly new relationship is going so well that they've even thinking about taking things to the next level: getting a pet!
"I don't know if Nick was joking, but she really wants a new puppy. He suggested, ‘Well, maybe we should get one together.'"
And as for why the two have seemed to click so easily, the insider says that it's partially due to the fact that they "understand each other's schedules."
"Olivia is pretty much confirmed to go on tour with him. He's buying her ticket. She has a few events, but she is going to go to as many shows as possible."
Nick is even going so far as to get in with the family and start things off on the right foot.
"He got along perfect with her brother and he clicked right away with her friends. He event went golfing with her dad!" the source added. "He's putting a lot of effort into getting to know them."
It looks like Nick is head over heels and absolutely smitten with his new leading lady. In fact, he's even been surprising her with little gifts as of late.
"He's always surprising her! Last week, he sent a candy basket, and the card said, ‘Just as sweet as you.'" Adorbs much?
"I know it's really soon, but I think they really love each other," the insider added.
The loved-up twosome were most recently spotted getting their PDA on at the 2013 U.S. Open Tennis Championships in the Lacoste Suite at the USTA Billie Jean King National Tennis Center in New York.
Brother Joe Jonas, and girlfriend Blanda Eggenschwiler, sat beside them in the stands seemingly unaware by the smooch session taking place.