The 49-year-old presenter intervened when conversations between the judging panel began to become heated.
Choirmaster Gareth Malone, former choirgirl turned international recording artist Kelis and this week’s guest judge singer songwriter Bebe Rexha disagreed over comments about Welsh choir Sgarmes.
Lead singer Emma pulled out a show-stopping performance, but Gareth mentioned that as a group, there were a few flat notes at the beginning of the song.
Gareth said: "Wow, that was absolutely great. Then you had that solo! You know what, it wasn't perfect, in tuning terms it wasn't as perfect as the girls in the middle. There were some tenors that were a little bit flat in the beginning."Related articles
BBCPitch Battle: Mel Giedroyc forced to step in amid Gareth Malone disagreement: 'Simmer down!'
Lads, come on, simmer down!