At around 3:10 the mention begins:
Translation on the Britney part:
Tiësto: "Yes, that's true. We are negotiating. I let her hear some tracks and she thought they were very good. So now we are looking for the right songwriter to write lyrics for the tracks."
Interviewer: "You met her?"
Tiësto: "No, I didn't meet Britney herself, but I met Theresa (?), her A&R manager. I had lunch with her and she told me that Britney was very enthousiastic about the tracks I sent her."
Interviewer: "Okay, so how does that work? You just think: 'I think it would be fun, with who do I want to work: Britney Spears!'?"
Tiësto: "Yes, well.." (interruption) "I made some tracks and my manager sent them to some artists, like Nelly Furtado and Estelle and Britney Spears. And all three of them want to work with me."
Translation by: oldsongs livejournal