Two of Kelly's acts - girls Sophie Habibis and Misha B - had to compete in the sing-off. After they both performed, sick Kelly made an appearance on the show via a telephone line from LA - croaky voice and all - and spoke of her "shock" that two of her performers were in the final two.
Despite Kelly's absence, she was still allowed to vote down the telephone, and she opted to send Sophie home, as did all the other judges. Stand-in judge Alexandra Burke was on stage to comfort the losing contestant.
Sophie had been accused of sounding like "a secretary singing at the weekend" the previous evening by Louis Walsh but, during the sing-off, she pulled out a much stronger performance than she had previously shown.
Meanwhile, Misha B - consistently the classiest performer of this competition so far - performed a relatively muted version of Use Somebody by Kings of Leon and finally gave into the pressures of the week, with tears pouring down her face.
It was a good week for judge Tulisa after all the drama of her big falling-out with rival judge Kelly over the last few days. Both her bands went straight through, despite each weathering controversial weeks that cut into their rehearsal time.
The Risk saw the loss of bandmate Ashley Baptiste, whom Tulisa had to replace with Nu-Vibe alumnus Ashford Campbell. Meanwhile, the newly-christened Little Mix were testing out their name for the first time since a very public battle with an established charity called Rhythmix forced them to find a new label.
Louis also had a relatively easy time of it this week, despite having the often tricky Over-25s category. Both his remaining acts Johnny - fast becoming the audience favourite - and Kitty, who had to perform in last week's sing-off - went straight through.
Gary Barlow had fewer problems this week, too, watching his acts Marcus Collins and Frankie Cocozza go through to the next stage of the competition.
Click through our Slideshow of all the contestants in this year's series and vote for who you think should win the competition...