The actor, who is rumored to be engaged to model Bar Rafaeli, partied with Petra at New York's Marquee nightclub on Friday (April 27, 2007).

A source told the New York Daily News newspaper: "He looked like he was all over her. They were together from before 12.30 a.m. to around 2.30 a.m.. He was holding her waist and touching her arm."

Leo was celebrating the launch of new movie "Gardener of Eden" - which he produced - at the Tribeca Film Festival.

The "Departed" actor also partied with Diddy, "Gardener of Eden" director Kevin Connolly, "Entourage" star Adrien Grenier, and tennis ace Andy Roddick.

Leo was alleged to have proposed to Bar, 21, during their recent trip to Israel. It is believed they plan to marry in the Middle-East country this summer.

Earlier this month, the 32-year-old dismissed rumors Bar was expecting their first child in autumn as "100 per cent made up."

Petra split from British singer James Blunt in February, following a year-long romance.