While leaving Giorgio Baldi with new girlfriend Shannon Costello, actor Sean Penn lost his temper with photographers ... spitting at the cameras!

The hot-tempered actor has had a history with paparazzi-involved scuffles. Back in 2009, Penn kicked photographer Jordan Dawes. As a result, the actor received 36 months probation and was ordered to serve 300 hours of community service.

As for this new relationship ... Penn, 51, and Costello, 26, went public as a couple last week, and over the weekend, the duo hit the streets in Malibu for a run.

jogging shirtless muscle

By the looks on Costello's face after Penn's spitting encounter, doesn't look like she's too impressed.