The 39-year-old was reportedly rushed to hospital on Thursday after collapsing, and was absent last night when her act Andrea Faustini was voted off of the show.
But an X Factor spokesperson tonight broke the news that she's been deemed well enough to return to the show.
Rick Behari, head of press for the show, tweeted: "After being discharged from hospital & after medical advice, @OfficialMelB is well enough to be on tonight's XFactor. We're glad she's back [sic]"
Former judge Tulisa, 26, stepped in for Mel last night, when Fleur East, 27, and 29-year-old Ben Haenow beat Andrea to a place in the grand final.
Mel's sister Danielle and mother Andrea sent a string of desperate tweets claiming that they were being kept in the dark as to where Mel was and what was wrong with her.
According to reports, Mel began screaming and complaining of stomach pains on Thursday, prompting her driver to rush her to hospital. She was then allegedly tested for viruses and a stomach ulcer.