Released as a single in 2003, "I'm Lovin' It (parapapapa)" is far more famous as a McDonald's advertising jingle than as an actual song. The single went nowhere in the US and barely cracked the charts in the UK, but it became the basis for a massive ad campaign launched by the fast food giant later in 2003, which made Timberlake a pitchman for the campaign. "Justin Timberlake is perfect for the McDonald's brand and our 'I'm Lovin' It' campaign, which is all about connecting with our customers in fresh, modern, relevant ways," the company announced in a press release. Timberlake obediently stated, "I love what McDonald's is doing with this new campaign and it's cool to be part of it. We share the same crowd - people who like to have fun - and that's what this new partnership is all about."
Timberlake sang on variations of the "I'm Lovin' It" jingle, which included the highly effective "para-pa-pa-pa" earworm. The genius of the campaign was how McDonald's managed to separate the jingle from the singer after Justin tore off part of Janet Jackson's shirt during the halftime show of the 2004 Super Bowl, exposing her breast and creating a panic among broadcast executives. Timberlake was a media pariah for a while, but by that point, McDonald's didn't need him - the "I'm Lovin' It" campaign was self-sustaining, and ran longer than any other in the company's history, even outlasting "You deserve a break today." They enjoyed substantial sales gains as the advertising hit the sweet spot, making consumers feel bright and happy about downing Big Macs which Burger King continued to push their Whopper with a bizarre King mascot. In 2010, McDonald's revived "I'm Lovin' It" for a new campaign, this time with no mention of Timberlake.