Justin Timberlake performed the vocals on McDonald's 2003 "I'm lovin' it" campaign song.
McDonald's launched the global "I'm lovin' it" campaign in 2003, using a short musical hook and the phrase as a central part of its advertising identity. Timberlake recorded the vocal performance associated with the campaign, and the song was released commercially as "I'm Lovin' It."
The campaign connected a worldwide restaurant brand with contemporary pop music and helped make the phrase recognizable beyond individual commercials. The wording later became McDonald's long-running advertising tagline, although advertising executions and translations have differed around the world.
The song is sometimes credited solely to the advertising campaign or confused with a later pop single. The relevant distinction is that Timberlake supplied the vocals for the 2003 McDonald's song used to launch the campaign.