Watch Mary Hart and John Tesh's Emotional Entertainment Tonight Special Reunion (Exclusive)

The legendary hosts reconnected on a very special episode of ET on Tuesday.

It's been quite a while since iconic Entertainment Tonight hosts John Tesh and Mary Hart sat together behind the ET desk, so their reunion during Tuesday's episode was something truly memorable.

Tesh and Hart joined up to host the show for the first time in over two decades, and the duo reminisced about the 10 years they spent side by side, delivering the latest in show business news.

Hart recalled how one of her favorite memories came from Tesh's taped audition, where the pop musician and TV personality first gave it a go at hosting, and really wanted the gig.

"I was in a flop sweat, I was really nervous," Tesh shared. "I really wanted the job, you were very sweet ...  [and] I sweated through a couple of shirts."

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From 1982 to 2011, Hart was the face of Entertainment Tonight, where she interviewed countless celebrities and superstars. During that time, she and Tesh co-hosted ET during his full run from 1986 to 1996.

The two previously reunited -- along with former ET co-hosts Rob Weller, Bob Goen and Mark Steines -- in 2011 to bid farewell to Hart on her final ET taping.

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During Tuesday's reunion, Hart also got emotional while talking with her longtime co-host and friend about his new book, Relentless: Unleashing a Life of Purpose, Grit, and Faith, in which he opens up for the first time about his recent battle with cancer.

Tesh was diagnosed with a rare form of prostate cancer in 2015 and is now in remission, and during his lengthy battle, he kept the diagnosis and his treatment largely quiet from the world.

"I think the reason for that was that I was just afraid of what would happen to my business, my family business if people were all of a sudden writing me off," Tesh explained. "The diagnosis was dire and my doctor… if he didn't find this cancer the way he did with the digital exam, I would not even be having this conversation."

According to Tesh, doctors said that he likely had around 18 months left to live when he was first diagnosed in 2015.

"They said they could probably guarantee me that. It was like pulling the tablecloth out from your setting," Tesh shared. "Immediately, I was paralyzed. My family was paralyzed."

Through the agony and emotional turmoil of treatment, Tesh found unending support from his wife of nearly three decades, Connie Sellecca, and their two adult children -- son Gib and daughter Prima.

Even through his lowest points, Tesh said he also found support in his faith and scripture, which guided him when he felt lost. And now, he hopes his battle with cancer can inspire others.

"We have purpose, we have grit, we have persistence. And then, when we have that all, when you mix in faith-filled words, you can become relentless doing anything," Tesh explained.

Tesh's memoir, Relentless: Unleashing a Life of Purpose, Grit, and Faith, is available now.