|Birthdate||June 25, 1984|
|Memorable Works|| The Phantom of the Opera|
Killian is from Kilmessen, in Country Meath, Ireland, where he was a member of the St Mary's Musical Society. He has one sister and one brother who still live in Ireland, while Donnelly takes up residence in London. Donnelly is a tenor and plays piano and guitar.
Donnelly has appeared in many different roles around Ireland and has also directed and written shows. His first theatre role was in 2005 where he featured in the chorus of The Wireman at the Gaiety Theatre, Dublin. He then continued to play Rod in Singin' in the Rain and Ethan in The Full Monty, both at the Olympia Theatre, Tony in West Side Story at the Solstice Theatre, Aladdin in Aladdin and Collins in Michael Collins: A Musical Drama, both at the Cork Opera House, Prince Charming in Cinderella at the Gaiety Theatre, Dublin and Chorus in Sweeney Todd: The Demon Barber of Fleet Street at the Gate Theatre.
In 2008, he joined the West End production of Les Misérables as a swing and, as a member of the cast, was part of the Les Misérables concert with the Bournemouth Symphony Orchestra on the Isle of Wight. He became second cover Javert and Enjolras in the following season of 2009/10, during which time he also performed the lead role of Jean Valjean as an emergency cover multiple times. With the following cast change he was promoted to principal Enjolras and was officially listed (and performed) as third cover Valjean. He eventually finished in Les Misérables on June 18, 2011.
Donnelly's next role was Raoul in Andrew Lloyd Webber's The Phantom of the Opera at Her Majesty's Theatre. During this time, he also featured in commercials for McDonald's and Jameson Whiskey, and appeared on such television shows as The Tudors, The Open House, The Late Late Show and Showbands. He later performed in You Should Be Dancing at the National Concert Hall.
On October 3, 2010, Donnelly played the role of Courfeyrac in the 25th Anniversary Concert of Les Misérables at The O2 Arena in London. He also played the role of Combeferre in the film of the show, released in 2012.
On November 12, 2012, Donnelly took over the role of Tony in Billy Elliot The Musical at the Victoria Palace Theatre.