Kostov was born inMoscow to aKazakh mother and aBulgarian father.[7] He has an older brother, Daniel, and a younger sister, Sofia.[8] As a child, he learnedBulgarian from his father, English from his brother, andKazakh from his grandfather.
Kostov participated inthe Russian version ofThe Voice. He was part of thefirst season of the kids version of the show where his mentor wasDima Bilan, who chose Kostov to advance to the finals.[10] After his success in Russia, Kristian auditioned for the fourth season ofX Factor Bulgaria as he is of Bulgarian origin.[11] He was selected as one of the three male contestants who advanced to the live shows and became one of the finalists.[12] During the finals, he performed theLyube's song "Позови меня" solo, a duet withVasil Naydenov for "Сбогом, Моя Любов", andEmil Dimitrov's song "Ако си Дал" as his winning song on the second night. When the final results were revealed, he was runner-up.[13]
On 7 October 2016, his debut single "Ne si za men" was released by Virginia Records.[14] The song peaked to number 13 on the Bulgarian Singles Chart. He featured on Pavell and Venci Venc's single "Vdigam Level", which was released on 25 November 2016, and peaked to number 13 on theBulgarian Singles Chart. On 13 March 2017, it was announced that he wouldrepresent Bulgaria in theEurovision Song Contest 2017 with the song "Beautiful Mess".[15] He finished in second place.
On 11 January 2019, Kostov was revealed as the last of the seven first-round performers competing on theseventh season ofChina's long-running singing competition,Singer, whose cast consisted of veteran Chinese singersLiu Huan,Chyi Yu,Yang Kun,Wu Tsing-fong, Zhang Xin, and Escape Plan. Kostov was also the youngest contestant inSinger's history at 18.[4][5]
^TopHit Weekly General chart "Mir bez voyny":"Дети земли - Мир без войны".Tophit. Archived fromthe original on 2020-03-28. Retrieved2017-05-12. The TopHit Weekly General chart's rankings are based on airplay on 230 radio stations in Russia, as well as 200 Russian-language radio stations all over the world (inUkraine, theCIS countries, theBaltic states,Cyprus, Israel, Germany, the United States, and Canada).
Names inBold indicate the winning singer, whileItalics indicate the runner-up singer. Singers are listed based on their original season appearances, returning singers (who participated in seasons 5 or 8) are not repeated.
Singers participated in groups are listed in parentheses. Initial singers first listed in order of official announcement, followed by Substitute/Challenge Singers in order of appearance.