The Let It Shine bands got some special help at their rehearsals ahead of tonight's live semi-final.
Last weekend saw the first of three live finals as Gary Barlow's talent show nears its climax.
The bands performed live for the first time and five boys went home leaving us with four bands in the semi-final: Five To Five, Drive, Nightfall and Iron Sun.
This week they were surprised by some celebrity help from stars of famous bands as they rehearsed their latest performances.
Frankie Bridge from The Saturdays, Girls Aloud's Kimberley Walsh and The Wanted's Jay McGuinness and Tom Parker dropped by to offer the boys tips and advice on everything from their singing and dancing to just getting along with their bandmates.
In the semi-final double bill tonight the four remaining Let It Shine bands will go head to head in a bid to impress the judges and audience at home once again with another five guys heading home at the end of the weekend.
Each band will again perform a brand new song and this week they will each need to include a dance break to keep their place in the competition and win a place in next week's final.
As well as their main performances, all four bands will be teaming up with Gary and his Take That band mates in an epic opening number.
The opening performance will see the remaining bands each perform a classic Take That hit, before they are joined on stage for a very special collaboration with Take That themselves, Gary Barlow, Mark Owen and Howard Donald to perform the song Shine.
Meanwhile, former Pussycat Doll Ashley Roberts will join Let It Shine as a guest judge for the semi-final tonight alongside Gary, Martin Kemp and Dannii Minogue.
In the results show the two bands with the lowest public votes will each perform a classic Beatles song in the dramatic sing off before five boys are sent home.
Let It Shine continues this Saturday night on BBC One at 6:55PM with the results at 20:45PM.