JUSTIN TIMBERLAKE: Which song is this?

[Engage]

Hey guys, I need help with finding the name of this Justin Timberlake/N'Sync song.

It's either a Justin Timberlake song or possibly an N'Sync song where Timberlake sings a little tune that makes the sound of "Doodoo." Something like this: "A-Doodoo-Doodoo-Doo-Di-Doodoo-Doo."

I spent a lot of time trying to make this as clear as possible as I know it's a difficult request, but I'd APPRECIATE any help!