Strictly Come Dancing was plunged into turmoil last night as one of its biggest stars was forced to quit after sustaining a serious injury while training. Her withdrawal adds yet more pressure to Strictly bosses – actor Kristian Nairn quit the series for medical reasons just last month. The Game Of Thrones star, 49, said: 'With a heavy heart, I have to step back from this season of Strictly Come Dancing. The actor has starred in the West End's Billy Elliot and even made the final of Sky's Got To Dance series in 2013 aged 18. His last-minute replacement, Emmerdale actor Kelvin Fletcher, went on to lift the glitterball trophy with dance partner Oti Mabuse.