Updated January 16, 2004 01:00 PM

After Jennifer Lopez partied with her former beau Sean “P. Diddy” Combs last Sunday — and was photographed later in the week not wearing her pink-diamond engagement ring from Ben Affleck — speculation ran high that the two had split.

Not so fast. Thursday night, Affleck — back from a European trip — and Lopez had dinner together in Miami Beach at Tuscan Steak restaurant, where “they were holding hands and kissing,” according to a source in the eatery. “They were extremely happy together.”

The two left in separate cars, and on Friday morning Lopez lounged by the pool at her Miami Beach home, where she was seen with the ring back on her finger.

By Saturday, Affleck, 31, had flown to Utah, where he spoke to the press about the upcoming season of his and partner Matt Damon’s TV series “Project Greenlight” (which has moved from HBO to Bravo), as well as his next movie and, inevitably, J.Lo.

Actually, since Lopez, 33, costars in his next movie, “Jersey Girl,” the subject of their relationship was fairly unavoidable, especially in light of how they bombed together onscreen last summer in “Gigli.”

As a result, says Affleck, as quoted by the Associated Press, “They’re not going to be so eager to sell it as a Ben-and-Jen movie. They can actually sell it for what it actually is, which is a movie about me and a young girl, and me trying to raise her.”

“Jersey Girl,” which is due to open in March, is about a widowed father who brings up a daughter, and the failure of “Gigli” could actually help in the selling of the new movie, Affleck said: “The one thing it prevents from happening is for the marketing people to sell it in a dishonest way.”

Lopez has a cameo role as the wife of Affleck’s character, but she dies 12 minutes into the movie, Affleck said.

As for their real-life relationship, Affleck told AP “everything’s going along fine. We’re good.”

And marriage? “There’s nothing to report,” he said.