"American Idol" will officially come to an end tonight, and after 15 years, host Ryan Seacrest is going to have a hard time saying goodbye.

Seacrest has been with the show since it started, and he knows that tonight's final episode won't be easy to handle. Every single year, new contestants come and go, and even the judges have changed, but he's the one thing that has remained the same since it all began in 2002.

"It's surreal," Seacrest said of the grand finale. "It's starting to sink in. But I don't think it will really hit me until I say, 'Goodnight, America,' that one last time."

Even his co-workers have realized that he's been having a hard time with this goodbye since the 15th and final season started.

"I think Ryan is really struggling with this," judge Harry Connick Jr. revealed. "Not that he wishes it could continue, but it is time to move to the next chapter for all of us. For him to keep his emotions in check is pretty amazing. He is the best in the business!"

Seacrest is a very busy guy with multiple jobs, and he doesn't plan on stopping just because the one that he's been with the longest is over.

"The reason why I have 10 things is because I'm always afraid I'm gonna lose five," he said of why he keeps so busy. "Nothing will replace ['Idol'] but I'm looking forward to the possibility of what might be next."

Tonight will be a huge night for "Idol," as many past contestants and winners will be coming back to perform. Two of the biggest winners to come out of the show, including season one winner Kelly Clarkson and season four winner Carrie Underwood, will return to the stage "one last time" to perform for the final night.

"It's been a remarkable journey, and I feel very fortunate to have been part of a show that made television history in countless ways," Seacrest said in May. "It's a show about chasing and fulfilling dreams, and truth be told, it helped some of my own dreams come true, too."

Find out who will be crowned the final "American Idol" winner on Thursday at 8 p.m. ET on Fox.