Madonna received death threats for defending Pussy Riot.
The 'Hung Up' hitmaker gave an impassioned speech at the Amnesty International Concert in New York last night, in which she described herself as a "freedom fighter" as she introduced the Russian group - who were jailed on charges of hooliganism motivated by religious hatred after performing a protest song in a Moscow cathedral - to the stage to address the audience at the Barclays Center.
She said: "The right to be free, to speak our minds, to have an opinion, to love who we want to love, to be who we are -- do we have to fight for that?
"I've always considered myself a freedom fighter since the early '80s when I realised I had a voice and I could sing more than songs about being a material girl or feeling like a virgin. And I have definitely paid for and have been punished for speaking my mind and for sticking my neck out for this kind of discrimination. But that's OK."
Madonna also admitted she was threatened with arrest for her performances in Russia in 2012 because they promoted "gay behaviour".
She added: "Needless to say, I did not change one moment of my show. 87 of my fans were arrested for gay behaviour - whatever that is."
And the 55-year-old singer - who raises children Lourdes, 17, Rocco, 13, David, and Mercy, both eight - also joked about the group's name.
She said: "I'd like to thank Pussy Riot for making pussy a 'sayable' word in my household. Now, my eight year olds say it all the time."
While Madonna and Pussy Riot didn't perform at the concert, stars including Cold War Kids, Lauryn Hill and Blondie performed a selection of their hits.