Which singer performed the McDonald's “I'm Lovin' It” promotional track in 2003?

Justin Timberlake performed the promotional track associated with McDonald's 2003 “I'm Lovin' It” campaign.

The campaign used a song connected with Timberlake's vocals while McDonald's built a broader advertising platform around the phrase. This helped the brand link its television commercials to contemporary pop music and reach audiences beyond traditional fast-food advertising.

The track was part of a larger creative project involving the advertising agency Heye & Partner and music collaborators. Timberlake's role is often remembered because he was already a major pop performer when the campaign launched.

The singer should not be confused with Pharrell Williams, who has had other connections with major commercial music and McDonald's-related cultural references. The answer here concerns the vocalist associated with the 2003 campaign track.