Pink will be singing her latest single 'Try', while show judge Contostavlos recently revealed that she would be tackling "a ballad" on the show.
The X Factor judge's performance neatly coincides with the release of her debut solo album The Female Boss.
Christopher Maloney, Jahmene Douglas, Union J and James Arthur are the four remaining acts competing for spots in this year's grand final.
All the acts will sing two songs next weekend and the tracks will have the themes 'Songs for You' and 'Songs to Get You into the Final'.
Caroline Flack joked on The Xtra Factor that it was "basically songs week".
The X Factor semi-final starts on Saturday, December 1 at 8pm on ITV1.
X Factor results show 8 - pictures:
Copyright: Ken McKay/Thames/Rex Features