Hollywood actors ROBERT DE NIRO and SEAN PENN joined forces to celebrate their respective birthdays last Friday (17AUG01). ANALYzE THIS (1999) star De Niro invited Penn to bring his friends and family to his Tribeca, Manhattan loft where they partied until the early hours.

De Niro entered his 58th year with the significantly younger Penn, who turned 41. Penn's FORREST GUMP (1994) star wife ROBIN WRIGHT and De Niro's twin sons AARON and JULIAN joined celebrities MARC ANTHONY, BILLY CRYSTAL and MIA FARROW.

The two birthday boys were miffed to discover that when their lit birthday cake came out, no one had a camera to snap them cutting the cake. Luckily, someone produced one just before the paparazzi-phobics' candles melted away. (ES/WNWDN)

Source: WENN