Rosa Isabel Mutya Buena ( muu-TEE-yə; born 21 May 1985) is an English singer and songwriter who rose to fame as a member of girl group Sugababes. With Sugababes, Buena had four UK number-one singles, an additional six top-ten hits and three multi-platinum albums. After leaving the group in December 2005, she released her debut solo album, Real Girl in June 2007. Buena returned to Sugababes with the original line-up in 2012.

In 2012, Buena and her former Sugababes bandmates Siobhán Donaghy and Keisha Buchanan confirmed their reunion. The original trio originally opted to release music under the name MKS (Mutya Keisha Siobhan), releasing one single, "Flatline", in 2013. In September 2019, the group officially confirmed their return as Sugababes. In May 2021, Mutya released a UK garage-inspired track entitled "The One" with electronic music-producer duo Ryuken on New State Music.