The TLC reality star, er, designer is enjoying a three-day trip to St.-Tropez, courtesy of Christian Audigier.
Jon, Hailey and Christian had lunch together on Saturday, where Jon doted on his new gal-pal.
"Jon was attentive with Hailey, pouring her drinks of water, as it was well over 100 degrees, but was listening intently to Christian," says a restaurant staffer. "They were holding hands...it was sweet."
But he left a jet-lagged Hailey later that night to go party...
Jon left her back at the hotel (see their fancy digs below) while he partied with Audigier at the glitzy nightclub Les Caves du Roy, where he drank champagne and danced until 5 a.m.
"Their bill there could have been as much as $50,000," says a club source. "They looked like they were having a lot of fun."
After sleeping in Sunday, the couple did some shopping in St.-Tropez port. That night, Jon left Hailey at the hotel again and went to a late, boozy dinner with Audigier at a friend's private villa.
"He looked drunk," says a source who saw Gosselin arrive in the lobby of his hotel at around 3:30 am. "But in St.-Tropez people drink wine every night with dinner."
Jon and Hailey head back to the States on Tuesday after a final business dinner with the designer tonight. "The Gosselin kids are going to model the clothes we have designed," Audigier tells E! Monday. "They'll be involved in the project...it will be fun for them."
We'll see what Kate has to say about that!
One source says it's no coincidence that Jon brought Hailey along on his trip.
"Jon coming on his own or Christian meeting him at an office in L.A. is not going to get them that much coverage," an insider says. "Jon walking around St.-Tropez in an Ed Hardy T-shirt with a new girlfriend on his arm is going to get them extra press inches, which is what they want."
Mission accomplished, apparently.