This image released by ABC shows, from left, Lionel Richie, Katy Perry, Ryan Seacrest and Luke Bryan on the set of "American Idol" in New York. The season premiere had a strong debut on ABC, reaching more than 10 million viewers. (Eric Liebowitz/ABC via AP)

Ryan Seacrest called in sick for 'American Idol' for the first time ever.

The 44-year-old star had to miss filming for Monday's episode due to illness, and it marks the first time he has been absent on a production day across all 17 seasons with Bobby Bones stepping in for the regular presenter.

He joked: "I am not Ryan Seacrest; I am Bobby Bones. Sadly, Ryan is sick, and I look most like him so they asked me to fill his shoes tonight. Ryan, love you, buddy. Hope you get better."

Judge Katy Perry joked that the absence proves Ryan - who has never missed an episode in the history of the show - is actually a real person rather than a robot.

Alongside a shocked face and robot emoji, she tweeted: "Proof that @ryanseacrest is human after all.

"And it only took 17 years for you to use your sick day, not bad #AmericanIdol #getbettersoonryan"

Her co-star Lionel Richie also commented on social media, and described him as the "hardest working guy" in the industry.

He wrote: "Wow, @ryanseacrest missing an @AmericanIdol show day is crazy! Hardest working guy in the business! #AmericanIdol #IdolDuets"

And fellow judge Luke Bryan weighed in too, and revealed Ryan was "feeling better" after missing filming several weeks ago.

He added: "We missed you for this one! Really thought you might be a robot but glad you're feeling better. Haha!"

Ryan - who was live tweeting as he tuned in for the episode - replied: "Just needed a quick maintenance check. I should be good for next week brotha"

In a video statement to viewers, he quipped: "Good evening, and welcome to 'American Idol'. Tonight is a unique show for me, because it's the first time in 17 seasons that I have missed the show

"Fact is, I woke up and was having a terrible hair day. I just couldn't go out in public. No, I really had to cash in on my very first sick day, but my friend and mentor Bobby Bones was kind enough to to fill in."