Jennifer Lopez and Ben Affleck, Hollywood's most high-profile couple, have split up, according to her publicist.

"I am confirming the reports that Jennifer Lopez has ended her engagement to Ben Affleck," her publicist said. "At this difficult time, we ask that you respect her privacy."

The break comes amid persistent rumors that the couple -- who were apart while Affleck, 31, attended the Sundance Film Festival and the European premieres of his film "Paycheck" earlier this month -- were growing apart. While Affleck was overseas, Lopez, 34, was seen partying in Miami with her old flame Sean "P. Diddy" Combs -- and going out minus her 6.1-carat pink-diamond engagement ring. Combs and Lopez both denied any romantic involvement, but the sightings only fueled talk that Bennifer was in trouble.

The latest breakup is not the first for the couple: The pair briefly split up after their elaborate September 2003 wedding in Montecito, Calif., was canceled. Affleck and Lopez then reconciled while in seclusion at their Georgia island hideaway, but there was no talk of rescheduling the wedding.

The two also weathered trouble last summer, after Affleck was spotted at a Vancouver strip bar. He vehemently denied any sexual misbehavior with the dancers, and Lopez stood by him.

Lopez and Affleck, who met while filming the critically savaged "Gigli" in spring 2002, became a couple in July that year as Lopez's marriage to Cris Judd (her second) collapsed.

Photo Bonus: Bennifer: The Way They Were