Lady GaGa started writing songs with RedOne on the day they met.

The 'Bad Romance' singer rose to fame after teaming with the Moroccan born producer - who has been behind almost all of her biggest hits - and the songwriter said that from the moment they met he knew they would form a formidable partnership.

RedOne - real name Nadir Khayat - told Hollywoodlife.com: "She'd just been dropped. And so I went to the Sony building and she was just like there, with the glasses, all of that.

"Then we started talking and she blew me away with her musicality - when we met it took five minutes, ten minutes of talk and we said, 'let's go into the studio'.

"On the way she started talking about rock she said Motely Crue, do you remember Motley Crue?

"Then she said, what about doing a song called 'Boys Boys Boys'. So we started singing and then by the time we were in the studio the song was created so I just had to do the track to go over what we were singing."

Gaga's 'Boys Boys Boys' later appeared on her debut album, 'The Fame'. RedOne also goes on tour with Gaga and said they wrote both 'Bad Romance' and 'Alejandro' while on the open road.

He added: "On the first tour it was a really regular bus, but it wasn't made to make music. Then when we were touring in the US they made it a studio in a bus, with everything built in. We're writing music in it as we drive down the road."