X Ambassadors
Songs: Unsteady - Blinding Lights - Boom - Sucker for Pain - Happy People (& Teddy Swims & Jac Ross)

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) - You'll Never Walk Alone (Ray Quinn) - When You Believe (Leon Jackson) - Wild Horses (Susan Boyle)

Xanadu (film)
Music from the Motion Picture (1980)
See also: Xanadu (musical), Olivia Newton-John, Cliff Richard & Electric Light Orchestra
Songs: Xanadu (Olivia Newton-John & Electric Light Orchestra) - Suddenly (Olivia Newton-John & Cliff Richard) - Suspended in Time - Magic (Olivia Newton-John) - All Over the World (Electric Light Orchestra)

Xavi
Also known as Joshua Xavier Gutierrez Alonso
Songs: La diabla

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

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

XTC
Songs: Senses Working Overtime - Making Plans for Nigel - Dear God - Mayor of Simpleton

XXXTentacion
Songs: Roll in Peace (& Kodak Black) - Hope - Moonlight - Falling Down (& Lil Peep) - Sad!