Rosa Isabel Mutya Buena (/mʊˈtiːjə/ muu-TEE-yə; born 21 May 1985) is an English singer and songwriter who rose to fame as a member of girl group Sugababes.

She has five brothers and three younger sisters, one of whom, Maya, died unexpectedly in 2002 and Buena subsequently dedicated a song to her on the Sugababes album Three.

Influenced by the new wave, dance, and pop music of the 1980s, the record enjoyed success in the UK, where it reached number two and went triple platinum.

According to an announcement on their official website, "[Buena]'s decision was based purely on personal reasons and she will continue to remain the best of friends with both [Buchanan] and [Range]".

[12] The last remaining original member, Buchanan, said upon Buena's departure, "...we will all miss Mutya, but we also knew there was still a place for bringing in somebody new who could help us carry on taking the Sugababes brand of music forward".

[13] Following her departure from Sugababes, Buena began working on her debut album in early 2006 after signing with her previous label, Universal Island Records.

[14] The first single to be released in the UK featuring Buena was a ballad duet with George Michael, titled "This Is Not Real Love".

"Song 4 Mutya (Out of Control)", her collaboration with dance duo Groove Armada, was released in the UK in July 2007 peaked at number 8.

[15] On 12 February 2008, Buena was dropped by her record label due to poor sales and charting positions from Real Girl and her last two singles, "Just a Little Bit" and "B Boy Baby".

Buena also joined an array of UK, US and Jamaican artists to feature on the debut single of the London-based urban/funky house production duo, NightShift.

The song is titled "Can You Persuade Me" and it also features MegaMan (So Solid Crew), DJ Ironik, Sisqó, Tanto Metro & Devonte, TQ, Steelo, Juxci D, J2K, Wretch 32, Sam Obernik and Mr. Vegas.

[18] The fourth line-up launched an opposition to the claim on the basis that goodwill and reputation in the mark and trading name "Sugababes" belongs to the partnership – not an individual.

[19] In September 2010, Buena contributed to six tracks on the album The Sound of Camden, which was recorded in Israel with music producer Roy Sela.

[21] Despite the announcement, Buena teamed up with City Boy Soul, a band consisting of ex-Damage singer Coree Richards and British rapper Gak Jonze, and digitally released "Be Ok" in January 2011.

[24][25][26] In January 2012, further circulations that the group would reunite were sparked, after both Buena and Buchanan tweeted they were in the studio with "two other females" and British rapper Professor Green.

(sic)"[27] Despite this, Scottish singer-songwriter Emeli Sandé confirmed to MTV UK that she had written new songs for Buena, Buchanan and Donaghy, saying: "Yes, that is true.

"[30] In July 2012, it was officially confirmed the group had reformed under the name Mutya Keisha Siobhan and were writing songs for a new album under Polydor.

[33] In 2019, she participated in the fourth series of Celebrity Coach Trip paired with So Solid Crew member Lisa Maffia.

[37] In February 2020, she released the single "Black Valentine", on which she has writing credit, in collaboration with London-based pop duo Electric Pineapple.

In 2022, Buena, as part of Sugababes, appeared at various festivals, embarked on a headline tour and released The Lost Tapes, an album consisting of their 2013 single "Flatline" and previously unreleased material.