JESSICA SIMPSON & JOHN MAYER TAKE THERE RELATIONSHIP PUBLIC

Now that Jessica Simpson and Nick Lachey have finalized their divorce and settled their estate, Jessica is finally taking her relationship with John Mayer public.

Simpson, 26, and Mayer, 29, spent a romantic weekend together in NYC, where the pop starlet was heard referring to the rocker as her “boyfriend.”

"They are dating,” a source close to Mayer tells Us Weekly. “They're boyfriend and girlfriend. She flew into NY and stayed at his place."

On December 30, the couple enjoyed a late lunch of tacos and passion fruit margaritas at the Mexican eatery Dos Caminos in SoHo (“He paid and they held hands on the way out the door,” says a witness).

Later that afternoon, they hit Barneys New York for a pre-New Year’s shopping date.

"John smiled playfully at Jessica as he held her arm," says an onlooker. "They were really affectionate. They didn't seem to care who saw them. They were out and proud as a couple and Jessica looked so happy."

Mayer strolled over to the adjacent men’s store to search for grooming products, while Jessica browsed the accessories department.

When she found a necklace that struck her fancy, Simpson told an employee she wanted to get Mayer’s opinion before deciding to buy it.

"I don't know,” she hedged. “I'm waiting for my boyfriend.”

When Mayer arrived, she modeled jewelry for him. "They seemed almost like a married couple,” shopper Stacy Thompson tells Us. “They both looked really happy and she looked beautiful.”

After the duo paid for their purchases, they prepared to leave, with Simpson hugging him tightly from behind while resting her head on his back.

The pair was still going strong the following night. Just after 2 a.m. on New Year’s Eve, they arrived at a Hudson Hotel party, plopping down on a couch in the V.I.P. area, as Simpson nuzzled Mayer’s face and put her leg up on his lap.

Mayer kissed Jessica’s head before getting up and mingling with the crowd. Jessica kept to herself on the couch but smiled whenever John sat back down with her.

At around 3:00 a.m. the couple, joined by gossip blogger Perez Hilton, headed off to NYC club Stereo and into 2007 together.