Carrie Underwood, Jennifer Hudson to Perform on Last 'American Idol' Episode

After 15 seasons, the hit show is finally coming to an end.

Thursday will be a big night on television as American Idol signs off for good after 15 seasons.

Read: American Idol Contestants: Where Are They Now?

Host Ryan Seacrest told IE: “What a run, what a series, what a season.”

The last Idol will be one of these two singers -- La'Porsha Renae or soulful crooner Trent Harmon-- both hailing from Mississippi.

Wednesday night, Renae, a 22-year-old single mom, was in tears, dedicating her final performance to her adorable baby daughter, who was in the audience.

Harmon, 25, who lives on his family's farm sang his heart out, then revealed he had kept a diary full of every critique the judges ever gave him.

Thursday’s blowout finale promises surprises and appearances from Idol alums Carrie Underwood, Jennifer Hudson and Fantasia.

Read: As 'American Idol' Ends Fox Looks To 'Empire' As Their Key Show

The judges are already feeling sentimental about the end of an era.

Harry Connick Jr. told IE: “I’m going to miss it a lot. I think Ryan is struggling deeply with this, not that he wishes this could continue, but it's time for all of us to move on to the next chapter.”

Keith Urban said he was “grateful to have been a part of these four seasons.”

Watch: The Most Memorable Moments in 'American Idol' History