Cacatian Thomassen has roots in Sweden, Norway, Finland and the Philippines.[2] He has spoken about being bullied in school and dropping out of school in first year of upper secondary school.[3]
In 2016, Cacatian Thomassen auditioned to take part in the twelfth season of Swedish Idol. During the Qualifying Week he took part in the fourth heat performing the song "Sure Thing", he failed to qualify for the Finals, but went through as a wildcard. He made it through the live shows to the final along with Rebecka Karlsson and Charlie Grönvall. On 9 December 2016 he won the contest. After winning Idol, Cacatian Thomassen released his winner's single "Playing with Fire". The song peaked at number 6 on the Swedish Singles Chart.
2018–present: Melodifestivalen
Liamoo competed in Melodifestivalen 2018 with the song "Last Breath", and finished in sixth place in the final. He also participated in Melodifestivalen 2019 with the song "Hold You" in a duet with Hanna Ferm; they finished in third place.[4] He then participated in Melodifestivalen 2022 with the song "Bluffin", where he finished in fourth place in the final. He was again selected to compete in 2024 with "Dragon";[5] he came first in his semi-final on 10 February 2024, directly qualifying for the final.
^"Sverigetopplistan – Sveriges Officiella Topplista"(Enter "Liam Cacatian Thomassen" into the search box and press "Sök" to see the search results.) (in Swedish). Sverigetopplistan. Retrieved 23 February 2019.