On January 28, 2016, it was announced that Karl will be playing the role of Phil in the musical adaptation of Groundhog Day, the role played in the 1993 movie by Bill Murray. The musical ran at the Old Vic Theatre London from Monday 11 July 2016 - Saturday 17 September 2016. Karl is currently reprising the role in the Broadway production of Groundhog Day, which opened on April 17, 2017. For his performance in Groundhog Day in London, he received the 2017 Olivier Award for Best Actor in a Musical. On August 15, 2017, the producers of Groundhog Day announced it would end its Broadway run on September 17, 2017, but that a national tour and a possible return to London would follow.