X Ambassadors
Songs: Unsteady - Renegades - Sucker for Pain - Jungle (Remix) (& Jay-Z) - Boom

X Factor
Joe McElderry, Leon Jackson, Same Difference, The X Factor Finalists, Alexandra Burke, Steve Brookstein, Shayne Ward, Leona Lewis, Susan Boyle, Jedward, Maria Lawson & Cher Lloyd
Songs: Hallelujah (Alexandra Burke) - A Moment Like This (Leona Lewis) - Summertime (Leona Lewis live) - The Climb (Joe McElderry) - Somewhere Over The Rainbow (Shayne Ward)

Xanadu (film)
Music from the Motion Picture (1980)
See also: Xanadu (musical), Olivia Newton-John, Cliff Richard & Electric Light Orchestra
Songs: Whenever You're Away from Me - Magic (Olivia Newton-John) - Xanadu (Olivia Newton-John & Electric Light Orchestra) - All Over the World (Electric Light Orchestra) - Don't Walk Away (Electric Light Orchestra)

Charli XCX
Charlotte Aitchison
Songs: Fancy (& Iggy Azalea) - I Love It (& Icona Pop) - Vroom Vroom - Speed Drive (Barbie (2023 film)) - 1999 (& Troye Sivan)

Xscape
Songs: Just Kickin' It - Understanding - My Little Secret - Keep On, Keepin' On (& MC Lyte) - Do You Want to