BUCHAREST, Romania — Actor Ethan Hawke on Saturday praised Madonna for her boldness in speaking out against discrimination against Gypsies, words that provoked boos from thousands of fans at her concert in Romania.

Hawke, visiting Romania to help promote his mother's charity supporting education for Gypsy children, placed the pop superstar alongside Bob Marley and John Lennon as part of a tradition of artists speaking out against racism.

"She transcended being a pop star," he told reporters. "She drew international attention and shone the spotlight on a level of racism and the need for greater education," Hawke said.

At an August concert in Bucharest on her "Sticky & Sweet" tour, Madonna called for an end to widespread discrimination against Eastern Europe's Gypsies, also known as Roma. Thousands of fans responded by booing her.

"I don't have an agenda, Madonna doesn't have an agenda. We aren't politicians," Hawke said.

Hawke, 38, was to speak later Saturday at the Ovidiu Rom charity Halloween ball. He and his mother, Leslie Hawke, the charity's president, were already dressed in costume: the actor in top hat and tails and his mother in a Japanese-style kimono, black wig and geisha-like makeup.

A pair of Madonna's Christian Dior shoes with autographed skyscraper gold heels are to be raffled off at the ball, which is to be held in the giant palace of the late dictator Nicolae Ceausescu. Among the other prizes is a gold chain provided by actress Vanessa Redgrave.

Hawke has been coming to Romania to support his mother's work since 2000, he said.

"I feel I can do something," he told reporters, "instead of being part of the problem."