"Ego" is a song recorded by American singer Beyoncé for the deluxe edition of her third studio album, I Am... Sasha Fierce (2008). The song was composed by Elvis Williams, Harold Lilly, and Beyoncé. "Ego" was officially remixed with additional vocals from hip hop artist, Kanye West. Initially planned to be released in January 2009 as the second urban single in the US along with the fourth US and third international single "Halo", the release of "Ego" was canceled and replaced by "Diva". "Ego" was later serviced as the third urban single, and fifth overall single in the US on May 19, 2009 alongside the sixth US and fourth international single "Sweet Dreams".
"Ego" was originally written for singer Chrisette Michele, who turned it down. It was eventually proposed to Beyoncé who used it for the deluxe edition of I Am... Sasha Fierce. In the song, Beyoncé sings about her love for the "huge ego" of her love interest. "Ego" was generally well received by music critics, many of whom praised the fact that Beyoncé opted to show some of her vocal limitations in a part of the song. Critics also noted that "Ego" could even have been placed in either disc of I Am.. Sasha Fierce as it combines elements of both sides of Beyoncé's split musical personality. The remix version of "Ego" was nominated for Best Rap/Sung Collaboration at the 52nd Grammy Awards.
"Ego" became the fifth consecutive song from I Am... Sasha Fierce to reach the top 40 on US Billboard Hot 100, peaking at 39. It reached number three on the US Hot R&B/Hip-Hop Songs and was certified gold by the Recording Industry Association of America (RIAA). Despite not being released elsewhere, "Ego" reached number 11 in New Zealand and number 60 in the United Kingdom, among others. Its music video was directed by Frank Gatson, Jr, and was co-directed by Beyoncé herself, thus becoming her directorial debut. A video was also filmed for the remix version of the song with Kanye West. "Ego" was a part of Beyoncé's set list on her I Am... World Tour (2009–10).