Dermot O'Leary hosts the fifth week of live shows, on the Big Band theme. The remaining acts will be keen to impress judges Simon Cowell, Louis Tomlinson and Ayda Williams - as well as the viewing public - and escape elimination in tomorrow night's results show, after Giovanni Spano departed last week. Ayda's husband and Groups mentor Robbie Williams is due to return to the judging panel next week, having missed several recent shows due to touring commitments in South America, so tonight will see a guest stepping into the former Take That star's shoes once again.