Lady GaGa ''broke down'' recording her track about rape.

The 'Pokerface' hitmaker - who was raped at 19-years-old - unveiled the song 'Til It Happens to You,' which she recorded for documentary 'The Hunting Ground', which explores rape on college campuses, but songwriter Diane Warren has revealed the 29-year-old found it incredibly hard to get through the full session.

Diane told PEOPLE magazine: ''It was very emotional for her. She couldn't even talk through it at times.

''I had heard she'd gone through this, so I knew she was the right artist. She broke down a few times. She was very emotional doing the song. She put her whole heart and soul into it.''

Meanwhile, the award-winning singer previously admitted she didn't tell anybody about the incident for a long time and instead turned to drinking to try and blank it from her memory.

She explained: ''I don't know what I was thinking. I didn't tell anybody. And I didn't even tell myself for the longest time.

''And then I was like, 'You know what? All this drinking and all this nonsense, you have to go to the source, otherwise it just won't go away. It will not go away.''