X Factor boss Simon Cowell has said controversial act Honey G is "fun and believable".
The music mogul made the comments after rapper Honey G performed Kriss Kross' hit 90s track Jump on the ITV singing show.
Contestants took on girlband and boyband hits in this week's show as they revived hits from groups such as Wham! and the Spice Girls.
Cowell told Honey G: "On paper this shouldn't work, and every week I keep thinking it's going to end - but then tonight, once again, you stepped up Honey.
"There are so many people getting their knickers in a twist over you. You know, music can be fun and you're fun, you're believable and you're entertaining. And by the way, backstage you are one of the nicest contestants we've had on the show."
Judge Nicole Scherzinger appeared to have a dig at one of the Girls Aloud songs performed on the show, saying "the song doesn't really go anywhere vocally".
The 38-year-old was commenting after Finnish singer Saara Aalto performed the song Sound Of The Underground, which was the first single released by Girls Aloud.
Former X Factor judge Cheryl was a member of the five-piece girl band created during ITV's previous reality show, Popstars: The Rivals in 2002.
Cowell made cat-like hissing noises as Scherzinger told Aalto: "I didn't know if I would love the song because I feel like the song doesn't really go anywhere vocally, and you have such great vocal capability.
"But you did your thing on it. Actually, you're bigger than that song and you did your thing on it and I love what you did," she added.
Contestant Sam Lavery welled up after she had performed the second Girls Aloud song on the show, their 2004 version of The Pretenders hit I'll Stand By You.
She told judge Sharon Osbourne: "It's just the first song that I have ever sang in my whole life that actually I have been able to read the lyrics through and actually get a connection with and be able to like."
Emily Middlemas took on former X Factor stars One Direction's What Makes You Beautiful and earned high praise from all of the judging panel.
Fan favourite Matt Terry sang George Michael's I'm Your Man and received a mixed reaction as judge Louis Walsh told him it was a "little bit karaoke for me".
Boyband 5 After Midnight closed the show with a performance of the Spice Girls hit Say You'll Be There.
The X Factor returns on Sunday night at 8pm.