Nelly and Christina Aguilera recorded a song together in 2004 called "Tilt Ya Head Back." The track, which was a part of Nelly's double album "Sweat" and "Suit," went on to have moderate success, but Aguilera wasn't originally part of the song. Pop star Britney Spears was initially the one singing Aguilera's lines and now a clip of the Spears version has been put out online.

According to E! Online, Singapore's Gold 905 radio station debuted 30 seconds of Spears on "Tilt Ya Head Back," which reveals to fans what the song first sounded like. The track was put together using a sample of Curtis Mayfield's "Superfly."

You can listen to the clip below:

In 2004 it would have been a good fit for Spears and Nelly to work together after they had both performed at the 2001 Super Bowl Halftime Show alongside Aerosmith, Mary J. Blige, 'N Sync and Run-D.M.C. However, MTV reported in 2004 that the producer of "Tilt Ya Head Back," Dorian Moore, said Spears' label, Jive, pulled her off the song because it was too "urban." It was an interesting choice for Jive, especially after Spears was coming off her album "In the Zone" where she had a song featuring the Ying Yang Twins called "(I Got That) Boom Boom."

Although it's not a recent song, Spears fans will be happy to hear new music from the 34-year-old singer. Spears last released an album in 2013, "Britney Jean," and she recently appeared on the single "Pretty Girls" with Iggy Azalea in May 2015. 

Nelly's music career has also been mostly quiet as of late. While there are rumors he could be working on his eighth studio album, the 41-year-old rapper's last release was 2013's "M.O." Nelly put out a single called "The Fix" in August 2015, but no album has followed just yet.

You can listen to the original Nelly and Aguilera version of "Tilt Ya Head Back" below: