In 2008 at age 13, Tanner was given the extraordinary opportunity to play the lead role of Billy in Billy Elliot the Musical in London's West End. Even though he would have to move nearly 4,500 miles away from home, this was an experience he could not pass up. Preparation for the role of Billy required a great deal of dedication and hard work. He was trained in acting, dialect, singing, dancing, and acrobatics, all of which had to be mastered in a matter of three months. He made his West End debut on September 29, 2008. During his run he was given the chance to perform in the Broadway production from April to June of 2009. He gave his final performance as Billy on September 26, 2009. It was the experience of a lifetime that he will never forget.