West's MTV outburst - courtesy 2009 MTV Video Music Awards
President Barack Obama has labelled rap star Kanye West a "jackass" for interrupting Taylor Swift's winning speech at the MTV Awards on Sunday.
West stormed the stage in New York to tell the crowd Beyonce should have won the prize for best female video.
Since then, he has called Swift personally to apologise.
Speaking before a TV interview, Mr Obama said: "I thought it was inappropriate, it's like she's getting an award, why are you butting in?"
He added: "The young lady seems like a perfectly nice person, she's getting her award, what's he doing up there?"
Chatting with CNBC reporter John Harwood, Mr Obama made an off-the-cuff remark: "He's a jackass."
The comments came to light after ABC News staff mentioned them on Twitter.
The network said some of its employees had overheard a conversation between the president and Mr Harwood and did not realise it was off the record.
The network apologised to the White House and CNBC and removed the Twitter posts.
An audio recording of the remarks was later posted on showbiz website TMZ.
Since the incident at the MTV Awards, West has admitted he was in the wrong and has said sorry.
Swift told ABC News Radio that the rapper called her after the ceremony. "He was very sincere in his apology and I accepted that apology," she said.
But she told the US chat show The View, that his behaviour had "rattled" her.
"I had to perform live five minutes later, so I had to get myself back to the place where I could perform."
West, who was booed every time he appeared on stage after the incident, also wrote on his blog afterwards about how sorry he was to have ruined Swift's big moment.
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