To decide the lowest scoring two couples, the judges’ scores from Saturday's show were combined with the results of the viewers’ votes.
This evening heralded the fourth time in the dance-off for Mark and his dance partner Iveta Lukosiute but Ashley and Ola Jordan were newcomers.
Mark and Iveta performed their samba to "I Just Can't Wait To Be King" from The Lion King for a second time, while Ashley and Ola danced the rumba once again to "A Whole New World" from Aladdin, complete with flying magic carpet.
Judges Craig Revel Horwood, Darcey Bussell, Bruno Tonioli and Len Goodman unanimously chose to save Ashley and Ola.
Mark accepted his defeat gracefully and paid tribute to Iveta, his "dear friend and fantastic teacher". "I have had a ball," he said.
Iveta added: "This is my first season and Mark made it so special and memorable. I enjoyed every minute with him, he made me laugh."
This Saturday's musicals-themed extravaganza saw model Abbey Clancy earn the first perfect score of the series for her salsa with Alijaž Skorjanec to "You Should Be Dancing" from Saturday Night Fever.
Before hosts Tess Daley and Claudia Winkleman announced the results, entertainment was provided by a professional group dance from the musical Fame and a performance of "Bring Him Home" from Les Misérables by award-winning opera singer Alfie Boe.
Next week's quarter final show will feature the return of the Swing-a-thon, in which the six remaining couples dance simultaneously and are voted off the dancefloor one by one by the judges until only one pair remains to take the maximum six points.
Ballroom business then proceeds as usual to decide which two couples will face the dance-off.