On 1 April 2010 it was said that Hietala would leave the band to concentrate on a choir career. 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. Hietala was the master of the Kuopio choir in the program's second season. He came second in the contest, losing in the finals to the Joensuu choir, headed by pop rock singer Ilkka Alanko. Tarot's single "I Walk Forever," from the Gravity of Light album, was performed for the first time by Hietala, Tommi "Tuple" Salmela and the Kuopio choir during Kuorosota 2010; other songs performed included "The Phantom of the Opera," which Hietala has covered with Nightwish as well.
In June 2010, Hietala joined the heavy metal supergroup HAIL! 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.