Mariah Carey has warned Lionel Richie not to be a judge on 'American Idol'.

The 47-year-old singer was part of the panel on season 12 of the singing competition, and she had such an unpleasant time on the show, she's advised the 'Hello' hitmaker to stay well away, following rumours he is set to sign on for the rebooted version of the talent competition.

Asked advice for Lionel, she quipped to 'Entertainment Tonight': "I would say, don't do it."

Mariah clashed with her fellow judge Nicki Minaj during her stint on the show, and believes she was "foiled" on the programme, which is why she wouldn't recommend the experience.

She explained: "Yeah, they just were trying to foil me when I went on there. So, you know, that's the only reason why I say that [to Lionel]."

Although the 'We Belong Together' singer is bitter about her own stint on the hit TV series, she thinks Lionel - who has Sofia, 18, Miles, 23, and 35-year-old daughter Nicole - would make a "really good" judge.

She added: "No, I'm only kidding. If he wants to do it, that'll be great. I think he would be really good at it."

Katy Perry has confirmed she will take part in the show and Mariah - who has six-year-old twins Moroccan and Monroe - thinks the 32-year-old singer will make a "good" panellist.

Speaking about the 'Roar' artist, she said: "She'll be good too. They both will be good."

And Ryan Seacrest - who previously hosted the talent show from 2002 until 2016 - is set to return to helm the programme when it returns to the ABC network next year.

The 42-year-old hunk has always wanted to make a comeback on the show.

Speaking previously, he said: "I don't know if you've ever been in a 15-year relationship, and then -- for a reason you don't really know - you break up. And I thought, 'Gosh, it would be great to get back together at some point.'"