Dean-Charles Chapman made his stage debut in 2005 in the London production of "Billy Elliot: The Musical." He started in the role of "Small Boy," and later went on to play the role of Michael, Billy's best friend. His performance was impressive, and in 2009, Champman moved on to play the musical's titular role. As of 2011, Chapman was the second longest running performer in the show, and the production's longest serving "Billy." In 2007, while still playing minor roles in the musical, Chapman made his television debut in an episode of the British medical drama series "Casualty" (BBC 1986- ). Chapman returned to the small screen again after leaving "Billy Elliot: The Musical" when he starred as Stanley Brown in the series "The Revolting World of Stanley Brown" (CBBC 2012). The series was a science-fiction adventure focusing on the life of a 13-year old boy whose whole world changes when his time traveling descendent pays him a visit. Chapman followed up this role with appearances in the TV series "The White Queen" (BBC 2013), "Glue" (BBC 2014) and "Ripper Street" (BBC 2014). In 2013 Chapman appeared on the medieval historic fantasy series "Game of Thrones" (HBO 2011- ) as Martyn Lannister. In 2014 and 2015 he appeared again on the wildly popular series, replacing actor Callum Wharry in the role of Tommen Baratheon.