Thus began a weeklong whirlwind in which the couple played peek-a-boo with the press. For example, on Monday they sat and smooched at a center table at Nobu (the same place where a teary Lopez dined with hip-hop mogul Sean 'Puffy' Combs, 32, last year just before breaking off their romance).

Two days later Affleck squired the birthday girl from the set of The Chambermaid (which stars Lopez as a hotel maid who catches the eye of a wealthy Ralph Fiennes) to the Park restaurant, where 30 friends surprised her for a celebratory lunch. "They were affectionate, sitting together and whispering," says a bartender. Affleck had his own surprise: a Harry Winston bracelet of yellow and white diamonds. When paparazzi converged, the two made a point of slipping out separate entrances. For the next three nights, as Lopez worked from 5 p.m to 5:30 a.m. shooting Chambermaid at the Met, Affleck hung out in her trailer. They ordered takeout and often left in separate chauffeured SUVs, with Affleck later hopping out to join Lopez. (In a thoughtful Felliniesque touch, there was even an Affleck lookalike walking around the set to fool photographers.) On the final day of shooting, in Yonkers, N.Y., last Friday, Lopez and Affleck snuggled for a set photographer. "They must have been kissing for 15 minutes," says an observer. "She looked so happy."

And ready to move. On Saturday the pair jetted to Lopez's recently purchased $9.5 million, 11-bedroom Miami Beach mansion, where she was planning a housewarming party. Instead, despite weeks of renovations (Bee Gee Robin Gibb was among neighbors complaining about the noise), the sound system wasn't working. "She was upset," says a staffer, "so she canceled all but having a few people in for dinner." Including Affleck, who was spotted smooching Lopez on her balcony before both headed to L.A. for business two days later, with Affleck due on the set of his superhero saga Daredevil.