What global McDonald's slogan began appearing in advertising in 2003?

“I'm lovin' it” began appearing as a global McDonald's advertising slogan in 2003.

The campaign marked an important change in McDonald's branding because it was designed for international use rather than being limited to one national market. The lowercase styling and short phrase were paired with a distinctive five-note musical signature.

The campaign originated from work associated with the German agency Heye & Partner and was adapted for McDonald's markets around the world. Justin Timberlake appeared in a related promotional music video, while the jingle became the central audio element of the brand campaign.

The slogan is often confused with earlier McDonald's lines such as “You Deserve a Break Today” or “We Love to See You Smile.” Those campaigns belonged to different periods. “I'm lovin' it” became one of the longest-running global identities in McDonald's advertising.