Arnold Schwarzenegger's ex Maria Shriver refuses to attend same party as Miley Cyrus

The estranged wife of Arnold Schwarzenegger had planned to attend Art Basel Miami with her brother Anthony Shriver, but cancelled upon hearing the Wrecking Ball singer - the pop star girlfriend of Maria's 21-year-old son Patrick Schwarzenegger - was scheduled to attend.

An insider said: "Maria was going to go to Art Basel to spend some time with Anthony, but when she heard Miley was going to be there with Patrick, she cancelled."

Miley, 22, was a last-minute booking for the event which was staged by Tommy Hilfiger and Jeffrey Deitch at the Raleigh.

However, she became the talk of the event after stripping down on stage to silver underwear, and dancing with a topless woman, as well as a man dressed as a penis.

The Party in the USA singer was also seen smoking what looked like marijuana on stage, which triggered an argument between Miley and Patrick.

A source told the New York Post's Page Six column: "Patrick is anti-drugs, but Miley doesn't give a f**k. She smoked marijuana on stage, and God knows what else she was on for the rest of the weekend.

"She and Patrick were heard fighting about it. There's no way Patrick can be linked to drug use; his family is American royalty."

It has previously been claimed Maria doesn't approve of Patrick and Miley's relationship.

Maria became concerned after seeing photos of Miley on a bucking bronco shaped like a penis at her 22nd birthday party last month.

A source explained: "The birthday party with all the penis pictures disgusted her. That was the worst thing Miley could have done.

"Maria is very, very worried about the influence Miley's having on Patrick. She fully believes that you become who you surround yourself with and she's always been so happy with the friends Patrick chooses, she never saw this coming."