Petra Nemcova has denied she is romancing Sean Penn.

The pair fueled speculation they are a couple when they arrived arm-in-arm for Elton John's annual AIDS Foundation post-Oscar party on Sunday.

However, the 28-year-old model claims the relationship is purely platonic, saying: "Yes, we are friends. He is on the advisory board of my charity."

Petra - who launched The Happy Hearts Fund for disadvantaged youngsters in 2005 after surviving the Indian Ocean tsunami tragedy - happily posed for photographers at the exclusive bash with Sean's arm around her waist. The couple also reportedly enjoyed each other's company at Los Angeles club Villa on Saturday.

Last year, Petra was accompanied by her then-boyfriend, 'You're Beautiful' singer James Blunt to the post-Academy Awards parties, though the pair split shortly after.

Sean, 47, recently announced his split from his wife of 11-years Robin Wright Penn, as both cited "irreconcilable differences".

In divorce papers the pair asked for joint legal and physical custody of their children, Hopper Jack, 14, and Dylan Frances, 16.

Sean was previously married to Madonna for four years, while Petra was engaged to British photographer Simon Atlee, who tragically died in the 2004 tsunami disaster.