Songfacts®:

• This song is credited to Eminem, Dr. Dre and 50 Cent. In late 2004, Eminem released "Encore," which featured the same three artists.
• An unfinished version was leaked under the name "Number One" on a mixtape in December 2008. Billboard magazine reported that this left Eminem, "really heated. It wasn't close to finished, and it even has me doing guide vocals for Dre as a suggestion of how he could lay his verses down. It's like someone catches you peeping in your window before you got the Spider Man costume all zipped up! Nobody is supposed to see that. We are gonna finish it up though and get it out there how it's supposed to be."
• This song's appearance in the Hot 100 marked Eminem's first appearance on the chart as lead vocalist in two years. His previous entry was "You Don't Know," which spent six weeks on the Hot 100 in December 2006 and January 2007.
• Eminem, Dr. Dre and 50 Cent are all billed as lead artists on this track. The previous time three male artists teamed up to record a #1 hit was in September 2003 when Nelly, P. Diddy and Murphy Lee reached the top position with "Shake Ya Tailfeather."
• In selling 418,000 digital copies, this set a new record for opening week download sales overtaking the 334,000 digital downloads sold by T.I.'s "Live Your Life" in its debut week. The trio only held the record for seven says as the following week, Flo Rida's "Right Round" sold 636,000 downloads.
• The song's video was directed by Syndrome, the production company behind Slim Shady's "3am."