The couple, referred to by fans and media as "Bennifer," reportedly broke up Tuesday, three days after Affleck returned to Los Angeles from the Sundance Film Festival in Park City, Utah, Access Hollywood's Web site reported Thursday.
While at Sundance, Affleck skirted questions about Lopez and their relationship, saying instead that he was ready for some down time.
"I'm not sure what I am going to do," Affleck said. "But I'm actually trying to relax a little bit. Take it down a level. This last year was a little nuts," Affleck said.
Lopez' office released a statement that said, "I am confirming the report that Jennifer Lopez has ended her engagement to Ben Affleck. At this difficult time, we ask that you respect her privacy."
The couple was last seen together for a public appearance when they arrived separately for Affleck's Hollywood "Paycheck" premiere in December. They also were seen in Las Vegas for New Year's.