Charlie Puth turned down 'American Idol' because the schedule was "too overwhelming".

Charlie Puth

Charlie Puth

The 'We Don't Talk Anymore' hitmaker was "honoured" to be asked to be a judge on the talent show but admits he had to turn it down when "Iife got crazy".

He told Entertainment Tonight: "The schedule got too overwhelming. It's nothing to do with [the network] ... ABC is wonderful and I told them I would love to be in business with them in the future. [I was in talks] and then things in my life got crazy.

"I can't wait to watch it. It's a huge honour that they asked me. The fact that they would even ask me to be a part of it is just beyond flattering because it's a show I grew up watching and I know it's going to be amazing without me."

It comes after Katy Perry - who will be a judge on 'American Idol' - championed Charlie and Lionel Richie, who has been given the job, to take up the remaining seat.

She shared: "I'm really pulling for Lionel, because I think Lionel Richie is an icon ... If you've ever seen or met Lionel, he just knows how to charm the whole room. His presence brightens the whole room. Charlie Puth is somewhat new to the general public of America. He has his own big fanbase, but I think he's really talented and Attention is one of my favorite things. He's young, fresh, cool, hip."

And Katy - who is joined by Luke Bryan on the judging panel - will not be listening to any "sob stories" from the show's contestants.

She said: "Sob stories come second for me. I just want to give constructive criticism - if you don't got the goods, you don't got the goods. The marketplace is already way too crowded, there's 100,000 things coming out every Friday - we don't need another person just to fill the space. We want a star and we need a star."