"Happy Birthday, Mr. President" is a song sung by actress and singer Marilyn Monroe on May 19, 1962, for President John F. Kennedy at a gala held at Madison Square Garden for his 45th birthday, 10 days before the actual date (May 29). The event was co-hosted by Arthur B. Krim and Anna M. Rosenberg, who sat next to the President during the star-studded event.Monroe sang the traditional "Happy Birthday to You" lyrics in a sultry, intimate voice, with "Mr. President" inserted as Kennedy's name. She continued the song with a snippet from the classic song, "Thanks for the Memory", for which she had written new lyrics specifically aimed at Kennedy.

Afterwards, as a large birthday cake was presented to him, President Kennedy came on stage and joked about Monroe's version of the song, saying, "I can now retire from politics after having had Happy Birthday sung to me in such a sweet, wholesome way," alluding to Monroe's delivery, skintight dress, and image as a sex symbol.The performance was one of Monroe's last major public appearances before her death less than three months later on August 4, 1962. First Lady Jacqueline Kennedy, who rarely attended Democratic Party events, instead spent the day at the Loudon Hunt Horse Show with her children, John and Caroline. Monroe was accompanied by jazz pianist Hank Jones.