From the moment Williams heard it she knew she loved it, but she also wanted to make sure she was the right person to sing it. Williams hopped on the phone with Zedd (aka Anton Zaslavski) to discuss the vibe of the song, which is a bit sexier than anything we've heard her do with her own band. Williams said she wanted to make sure she did the track justice.

"I think honestly, I was just nervous, you know?" Williams admitted. "But once I was in the studio, I think the process of singing it over and over and over again and starting to feel that it was in my blood, I felt great about it."

With the two unable to hit the studio together, Williams also wanted to make sure it didn't end up sounding disjointed, as if she just added her vocals over an already existing beat. To make herself more comfortable with the song, Williams wrote the lyrics, finishing them the day before she recorded.

"I was actually getting into the shower and it just happened," Williams explained. "The words just came to me and I got out immediately and wrote everything down."

Within five days of receiving the offer to appear on the song, Williams was in a Paris studio laying down her vocals. "We took a cab to this random studio someone from our label found," she explained. "We showed up and [the studio] had everything ready: the track up, hot tea and all that stuff."

Right after she finished, she jumped in a cab with her bandmates and headed off to the Stade de France where they were playing a show with Muse. "It was a really bizarre thing for me," she said. "I've never experienced anything like it, but it was so much fun."