Sean Penn, 52 thinks his ex-wife Madonna is "so hot," according to Us Weekly.

An onlooker who attended Madonna's concert on October 11 in Los Angeles, spotted Penn in the audience and heard him rave about Madonna, 54.

"The chemistry was off the charts," the anonymous source said."Madonna seemed to be performing entirely for Sean. And he was saying things like 'Amazing," and 'She's so hot!" the source added.

Numerous media outlets reported about Penn "secretly" attending his ex-wife's MDNA gig at the Staples Center wearing a baseball cap and a black leather jacket.

Penn and Madonna's four-year high-profile marriage in the 1980's is mostly remembered as a violent relationship. Penn infamously beat the "Material Girl" singer with a baseball bat around the head during a nine-hour attack.

He is also said to have tied Madonna to a chair and beat her.

A decade after their split, Penn admitted in an interview that he had drinking problems during his marriage to Madonna.

"I was not of sober mind during most of it," he said.

The ex-couple were married from 1985 to 1989. They met on the set of the music video "Material Girl" in 1985 to whom she referred as "the collest guy in the universe."

They're said to be friends now.

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