Maddie Poppe, Gabby Barrett and Caleb Lee Hutchinson went to head to head in the most recent episode.They had to perform three songs each: one of their single, one song from a past performance and one dedicated to their hometown. And that was before the win.
She wins a recording contract and a $250,000 cash prize.
Poppe and two other competitors sang three songs each during Sunday night's competition.
Harmon - who recently released his first album, You Got 'Em All - won Season 15 of American Idolin April 2016, with fellow contestant La'Porsha Renae coming in as the season's runner-up.
For fans who can't wait for Fall 2018, they can catch American Idol's Top 7 finalists as they prepare to hit the road for a nationwide tour this summer. Hutchinson is slated to sing "Wagon Wheel" with Darius Rucker.
After having fun with the stellar performances, host Ryan Seacrest revealed the first finalist to make it to the Top 2. He said Caleb and Maddie are a couple! They were absolutely shocked when Rimes herself came out and joined them. To her surprise, it wasn't Katy Perry, Richie or Bryan who commented on the performance, but former Journey singer Steve Perry - who sang the original track - offering his take.
Yolanda Adams and Michael J. Woodard, backed by a choir, performed Jackie DeShannon's "What the World Needs Now". The American Idol finalists were given a masterclass on how to command a stage courtesy of the country music superstar that has been guiding them all this season.
Taking the mood to a new level, cast-off Ada Vox then took the stage with a huge wig and train for a sensational performance of "Lady Marmalade".
But who won? After the two-hour special, Maddie was named the victor!