"American Idol" desperately wanted Katy Perry to fill one of its vacant judge's seats, so much so, they offered her $20 MILLION ... but she she still turned it down ... TMZ has learned.

Sources close to the production tell TMZ ... "Idol" pursued Perry relentlessly for weeks, eager to get her to sign on the dotted line. According to our sources, they started the offer at $18 million, but threw even more cash on the table ... $20 MILLION for a one year contract!!!

We're told Katy made it clear ... she was NOT interested and money wasn't the issue.

Sources tell us ... aside from the fact that Katy's schedule made it impossible to do the show ... she just didn't think it was right career choice for her.

Mariah must be one pissed, $18 million judge.

Read more: http://www.tmz.com/2012/08/25/katy-p...#ixzz24ZK6lAtB

Good.

She would have been paid higher than MARIAH?

The new queen.

lol flop source.

$20 MILLION? That's an insane amount of money.

She would've been the highest paid judge.

Focus on your next album.

If Britney had to struggle to get a 15 Million X Factor contract I doubt this is true.

Actuallt, TMZ is a very good source. They are rarely wrong.

DAMN

Katy would have been paid higher than Brit or Mariah. The new queen

Queen of Pop tbqh.

+1 respect

You're welcome!

Anyway that's crazy but I don't doubt they offer that amount the money considering she's the biggest pop star in US rn.

Uh, TMZ is reliable

. Good on her.. She wasn't that good of a guest judge on X Factor anyways... then again, she gets paid millions to do something she isn't good at now

This.

She would've been a great addition, she's been an excellent guest judge. I say it would've been well-spent money.

They're so desperate now, they should just ed the show.