The pair found themselves in the dance-off against Jamelia and Tristan MacManus, after the judges' scores were combined with the viewers' votes.
Strictly Come Dancing Week Six: All the scores and judges' comments
Gallacher and Cole performed their Charleston to Postmodern Jukebox's version of 'Bad Romance', while Jamelia and MacManus jived to The Rocky Horror Picture Show's 'The Time Warp'.
Craig Revel Horwood, Darcey Bussell and Bruno Tonioli all voted to save Jamelia and MacManus, sending Gallacher and Cole home.
Head judge Len Goodman said he agreed with his fellow judges' decision.
It marked the first time that a female celebrity has been eliminated from this year's show, following four successive male exits.
Jamelia found herself in the dance-off for the second consecutive week and for the third time this series.