Both contestants received the lowest points totals after the judges' scores were combined with the results of the viewers' votes.
They performed their highest scoring routines, with Lisa and partner Robin Windsor dancing the American smooth to All That Jazz from the musical Chicago, and Van Outen and James Jordan dancing the tango to Roxanne by The Police.
Both pairs received standing ovations. The unanimous vote meant Lisa became the 10th celebrity to exit the competition, leaving Van Outen, gymnast Louis Smith, Girls Aloud star Kimberley Walsh and actress Dani Harmer as the celebrities battling it out for the glitterball trophy in Saturday's final.
Lisa wept as she left the show.
"It's been the best time of my entire life, I can't thank you enough," she said.
"And one person has made that and that's Robin Windsor. He has just been amazing."