X Ambassadors
Songs: Unsteady - Sucker for Pain - Renegades - Ahead of Myself - 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) - Against All Odds (Steve Brookstein) - Somewhere Over The Rainbow (Shayne Ward) - Don't Call This Love (Leon Jackson)

Xanadu (film)
Music from the Motion Picture (1980)
See also: Xanadu (musical), Olivia Newton-John, Cliff Richard & Electric Light Orchestra
Songs: Magic (Olivia Newton-John) - Suddenly (Olivia Newton-John & Cliff Richard) - Suspended in Time - Dancin' (& Olivia Newton-John & The Tubes) - Whenever You're Away from Me

Charli XCX
Charlotte Aitchison
Songs: Fancy (& Iggy Azalea) - 1999 (& Troye Sivan) - I Love It (& Icona Pop) - Beg for You (& Rina Sawayama) - Boom Clap (The Fault In Our Stars)

Xscape
Songs: My Little Secret - Do You Want to - Understanding - The Arms of the One Who Loves You - Keep On, Keepin' On (& MC Lyte)

XXXTentacion
Songs: Look at Me! - Changes - Moonlight - Sad!