Sean Penn partied with his new girlfriend Charlize Theron at his ex-wife Madonna's after-Oscars party on Sunday (02Mar14).

The Monster star attended the prizegiving ceremony solo, but met up with Penn at the singer's seventh annual awards show bash.

A source tells Us Weekly magazine, "(They were) making out like crazy (and) all over each other. They were the talk of the party - even Madonna noticed!"

Penn and Madonna were married from 1985 from 1989.

He began dating Theron in February (14).