Sean Penn's new main squeeze

Sean Penn has begun dating Shannon Costello, a producer and the former communications director of Penn's J/P Haitian Relief Organization.

The Oscar winner -- formerly married to Madonna and Robin Wright -- was most recently linked with Scarlett Johansson.

Penn and Costello have been photographed together since the beginning of July, People magazine said Thursday.

Costello, 26, and Penn, 51, met in the fall of 2009 and became friends before she began working with J/P in 2010. She did rights and clearances research on director Davis Guggenheim's 2010 documentary "Waiting for 'Superman,' " and worked at ABC News' "20/20," the magazine said.

Deadline.com reported earlier this month that Costello is a producer with Brian Grazer, Jason Bateman and others on director Ron Howard's in-development film "Under the Banner of Heaven."

She and Penn have been seen together on the beach in Malibu and at the restaurant Nobu there, where they were photographed holding hands in the parking lot, as well as dining in Miami and jogging and running errands in Los Angeles.