Released as the album's third single on October 18, 2004, the song was written by Kelis and André 3000, produced by the latter, and contains a sample of the 1985 song "La Di Da Di" by Doug E. Fresh and Slick Rick.

Like Kelis' previous single "Trick Me", "Millionaire" was not released in the United States as her American label Arista had folded.

The song peaked at number three on the UK Singles Chart, earning Kelis her third consecutive top-five single, while becoming a modest commercial success internationally.

The accompanying music video, directed by Giuseppe Capotondi, does not feature Kelis or André 3000, but instead features children appearing as the duo's younger selves.

"Millionaire" debuted at number three on the UK Singles Chart, becoming Kelis' third consecutive top-five entry from Tasty.