Sources with direct knowledge tell TMZ ... Carrie and her team are in the final stages of locking her into a contract to appear on the hit ABC show -- and if all goes smoothly, the former 'Idol' winner will soon join Luke Bryan and Lionel Richie as the new judge.

What's also interesting about this news ... Carrie actually has an appearance scheduled on 'GMA' this upcoming Friday -- for their summer concert series -- but of course ... an official announcement could come that day as well. As you know ... ABC is the parent company.

If/when the deal is locked -- which we're told could happen any day now -- Carrie will be one busy superstar ... especially since she’s also extended her Las Vegas residency at Resorts World through 2025.

Here's the thing ... that extended residency only amounts to an extra 6 shows, giving her schedule a ton of flexibility to fit filming for 'Idol.' So in other words ... she can do both.

Having Carrie as a judge would be a HUGE get -- as she’s literally one of the show's biggest success stories since winning season 4 way back in 2005 ... a full circle moment, indeed.

It goes without saying ... Carrie’s killed it in the music biz -- selling 85 million records worldwide and scooping up 8 Grammys along the way. So yeah ... she definitely knows a thing or two about making it big in the music biz.

As for Katy, she got a sweet sendoff during last season’s finale in May after deciding to leave and focus on her own music career.

KP joined Idol in 2018 when it made its ABC comeback after years on Fox. She, Lionel, and Luke swapped places with the old-school legends Simon Cowell, Paula Abdul, and Randy Jackson.

With Carrie soon on board, it’s clear the show’s star power ain't going anywhere -- if anything, it's only growing. In the words of Ryan Seacrest ... "Dim the lights, here we go!"