The American Idol judge, who announced her split from husband Marc Anthony over the summer, celebrated the New Year with new beau Casper Smart in Miami Beach for a weekend of dancing, dining and cruising.
The pair, who stepped out together in November, started their hot weekend on Thursday with a night outing to club Amnesia. (The couple rocked special glasses to take in the lighting at the high-tech hotspot.)
“They were very sexy with each other, dancing and bouncing around and making out,” a source at the club tells PEOPLE of the couple, who partied until 3 a.m. “They couldn’t help but attract attention, although Jennifer was trying to lie low from onlookers.”
Adds another source: “Jennifer looked very happy. Although she kept to herself, there was no question she was really enjoying the club and her boyfriend.”
When they awakened early afternoon on Friday, Lopez, 42, and the L.A.-based dancer, 24, her 3-year-old twins in tow, boarded a $10 million-yacht owned by a friend.
“Jennifer and Casper held hands and had their arms around each other,” a source tells PEOPLE of their day-to-evening cruise. “The twins were having fun, and everyone seemed to get along.”
On Saturday, Lopez, accompanied by her daughter, another female and two bodyguards, headed to the Bal Harbour Shops.
Among her purchases at the outdoor Mediterranean-style mall: clothes and accessories from the Dolce & Gabbana and D&G stores, as well as a bikini from Pucci and some casual outfits for her little ones from baby store Bonpoint.
To ring in the New Year, a source tells PEOPLE that the couple joined a group of friends for a private dinner at the Soho Beach House. On Sunday, it was full speed ahead for Smart, who Tweeted about driving go-carts with some of his pals.
The couple stayed at a private home for the weekend. “Jennifer wants to keep a low-profile and has been using sunglasses and a plain face” with little or no makeup to go unrecognized, a source in Miami tells PEOPLE.
Also heating up Miami: Rihanna, who celebrated the New Year at Diddy‘s Star Island estate, and Paris Hilton and celebrity deejay Nick Van de Wall, who hit up Wet, a poolside party at the W South Beach.