The three remaining couples sing two songs, one from the only genre that they have not yet performed, the other a song that their professional partner has made famous, then the couple with the lowest score, combined from the judges scores and viewer votes, is eliminated.
- Tonight is semi-final time, with the champion set to be crowned at the end of the following week's episode. Host Grant Denyer introduced co-host Kate Ritchie, who was dressed in a stunning Aldo Terlato black and white gown, the judges, whom he described as the "pundits on the panel" - Marina Prior, James Valentine, Amanda Pelman and Ross Wilson - the house orchestra, led again by Chong Lim, and the three remaining couples, who had so far performed songs from all of the genres featured in this series except for one. Tonight, the first of two songs the couples would perform would come from this elusive genre, while their second song would be one that their professional partner has made famous. Grant also informs the viewers that two of the series' favourite professional singers who had already been eliminated, Troy Cassar-Daley and Wendy Matthews, would perform a duet together later, and that the voting lines had now closed.
First to step up to the microphone tonight are breakfast radio presenter Jo Stanley and her best-selling partner Anthony Callea, who perform Chuck Berry's Rock 'n' Roll hit Johnny B. Goode, rocking out in 1950's style as they burned up the dance floor with a group of dancers. After their performance, Grant interviewed them, and Jo revealed that it has always been her dream to perform as a wedding singer, while Anthony said that it was all about entertaining. Next, the judges deliver their verdicts, and Marina remarks "Fantastic - really great energy", while James thought that they were "really good". Kate then chats to the couple when they return to the green room before the judges reveal their scores - Marina scored them 9 out of a possible 10, James 9, Amanda 9 and Ross 8, for a total of 35 points.
Hitting the stage next were environmental businesswoman Mimi Macpherson and her opera partner David Hobson, with a performance of Nina Simone's slinky Swing classic My Baby Just Cares For Me. In the chat with Grant afterwards, Mimi said that she learns something new every week in the competition and thanked the judges for their guidance. In the judges' comments, James said, "I can walk into a hotel lobby anywhere in the world and be happy to hear that, wonderful, Ross remarked that tonight, Mimi was a "revelation", while Marina was impressed by David's "brilliant mentoring". All four judges scored them 9, for a total of 36 points.
Up next were All Saints actress Jolene Anderson and her theatrical partner, David Campbell, who performed a powerful rendition of the Queen song Somebody To Love, which was used in the movie "Happy Feet". They brought the audience to their feet with a fiery and electric performance that came complete with a backing choir. Afterwards, Jolene said to Grant "That felt fantastic!". In the judges' remarks, Amanda was "flabbergasted", while Marina told them that "vocally you get stronger every week, and this week, you nailed it". Marina scored them 9, James 10, Amanda 9 and Ross 10, for a total of 38 points.
Now that the couples had performed songs from every genre, Jo Stanley and Anthony Callea were the first to return to perform a song made famous by their professional partner, in their case, an uplifting duet of Australia's highest selling song The Prayer which brings a tear to Jo's eyes. After the performance, Jo tells Grant that the entire week has been "really overwhelming", but the performance was a "once in a lifetime opportunity to sing this song" with Anthony, and Anthony then adds that he is "so proud" of Jo. When the judges make their comments, Ross said that Jo "thrilled" him, Marina said that she was "knocked out", and James remarked that "the degree of difficulty in performing a song like that is very high, so just having a go is good on you". Marina scored them 10, James 10, Amanda 10 and Ross 9, for a total of 39 points.
Jolene Anderson and David Campbell were the next to return to the stage to perform a party favourite of David's, the swing song Can't Take My Eyes Off You. Jolene had another chance to show her sense of fun when one lucky audience member got to dance with her. When the judges delivered their verdicts, Marina commented that they were "classy, loose, free - wonderful!", James couldn't wait to hear more from Jolene in her new-found singing career, and Ross remarked that he couldn't take his eyes off Jolene, to which David replied "if we're having fun, everyone else is having fun". Marina scored them 10, James 9, Amanda 9 and Ross 9, for a total of 37 points.
The last couple to perform were Mimi Macpherson and David Hobson, with Mimi following in David's operatic footsteps for a show stopping performance of La Ci Darem La Mano, from Mozart's opera Don Giovanni. Mimi masters not just the operatic vocal stylings but also the Italian lyrics, while the performance, which Mimi later told Grant was a "wonderful experience", is a first for the series, with the couple dressed in full period costume and supported by a classical ensemble conducted by Chong Lim. In the judges' remarks, Amanda said "Congratulations! Fantastico!", Ross was "just floored" by the whole thing, and Marina declares "Brava diva! I take my hat off to you". Marina scored them 8, James 8, Amanda 9 and Ross 8, for a total of 33 points.
While the three couples waited to see who would make it to the grand final, two of the professional singers eliminated from the series earlier, Troy Cassar-Daley and Wendy Matthews, returned to the stage as the night's special guests for a performance of the Australian rock classic I'd Die To Be With You Tonight by Jimmy Barnes.
Then it was time to reveal the verdict and find out which couples would return for the following week's grand final, with the judges' scores and viewers' votes added together to determine the results. The safe couple, who had received the highest combined score, was revealed first, then the two other couples had a few more tense moments to wait before it was revealed that Mimi and David were eliminated tonight, leaving Jolene and David to compete against Jo and Anthony in the grand final. As Mimi and David prepared to reprise one of their earlier performances, Grant informs the viewers that the voting lines are now open.