Marko Tapani "Marco" Hietala (born 14 January 1966) is a Finnish heavy metal vocalist, bassist and songwriter.

Internationally, he is best known as the former bassist, male vocalist and secondary composer to Tuomas Holopainen, of the symphonic metal band Nightwish.

[2] He is also a member of the supergroup Northern Kings, and portrayed one of the main characters in Ayreon's 2013 album The Theory of Everything.

Hietala lived in Tervo until the age of 15, after which he moved to Kuopio to study classical guitar, vocals and musical theory in high school.

Shorthaired guys just standing there – Tarja was a pretty girl but just as petrified, shrieking in the middle of the stage in her leather pants.

[8] He was a prominent guest musician in Delain, a project involving many members of the gothic and symphonic metal community.

's "Wild Child", Dio's "Don't Talk to Strangers", Megadeth's "Symphony of Destruction" and Pink Floyd's "High Hopes".

Following Turunen's departure from Nightwish, Hietala was much more involved with the production of Dark Passion Play, which was released in September 2007.

Hietala is also credited alongside Holopainen for co-writing the song "The Crow, the Owl and the Dove" from Nightwish's 2011 album, Imaginaerum.

This was identified as an April Fool's joke, but was also a reference to his participation in Kuorosota (the localized Finnish version of Clash of the Choirs) in 2010.

He came second in the contest, losing in the finals to the Joensuu choir, headed by pop rock singer Ilkka Alanko.

on two occasions, performing Black Sabbath's Neon Knights with Ripper Owens, Andreas Kisser, James LoMenzo and Paul Bostaph at two of their shows in Finland.

[13] On 14 August 2013, Hietala was the first singer to be confirmed by Arjen Lucassen to guest on Ayreon's new album The Theory of Everything.

[15] An English version of the album, titled Pyre of the Black Heart (Nuclear Blast), followed in January 2020.

[16] Joining him on the albums are drummer Anssi Nykänen, keyboardist Vili Ollila and guitarist Tuomas Wäinölä with whom he also toured in Finland in the summer and autumn of 2019.

and in part due to the respite brought by COVID-19 pandemic, Hietala finally reached the conclusion that leaving the band would prevent his illnesses from worsening.

[19] Ten days later, Swedish symphonic metal band Therion released a music video for the song "Tuonela" that featured Hietala.

Writing and listening to music would become stale if I couldn't draw influences from other styles too.Hietala has two children with his ex-wife Manki, twin boys Antto and Miro (born in 2001).