Andrew Rannells confirmed he had a “very brief relationship” with Anderson Cooper over 20 years ago.

The actor made the revelation during a recent episode of Daily Beast’s “Obsessed: The Podcast,” explaining his “Girls” character Elijah’s short-lived relationship with a fictional television host was based on his time with Cooper.

“I told Lena [Dunham] and [co-creator] Jenni Konner a story about when I was 25 that I had dated Anderson Cooper, and I told them about the experience and what that was like,” Rannells said.

It then became Elijah’s storyline on Season 5 of the HBO series, which ran for six seasons from 2012 until 2017.

Rannells, who is now 47, added that the co-creators thought it was a “fun story.”

During Season 5, Elijah and Dill Harcourt (Corey Stoll) had a dalliance before splitting over their age difference, with the latter confessing he wanted to date “someone less aimless.”

In 2016, when the season aired, Stoll told Queerty that he “did not base this character on anybody.”

“I won’t comment on it,” the actor said about rumors his character was inspired by Cooper, who is 12 years Rannells’ senior. “I was playing Dill Harcourt.”

Cooper, now 59, told The Post, at the time, “I thought he was more of a [Bill] O’Reilly character.

“I just met Lena Dunham at Sundance and she didn’t mention anything to me, but I’d be flattered,“ he mused. “I’m a friend of Andrew’s. I should ask him.”

After Elijah and Dill’s breakup, Rannells said to Elle, “I think the general idea that he’s this powerful, you know, adult, is what’s important.

“We were in this very grown-up situation,” he elaborated about the character. “That’s what Dill represents.” 

The former flames, meanwhile, both moved on to other relationships after their fling.

Rannells has been with Tuc Watkins since 2019 — a year after the two first met while co-starring in the Broadway show “The Boys in the Band.”

For his part, Cooper dated Benjamin Maisani from 2014 to 2019.

After their breakup, the pair decided to welcome sons Wyatt, 6, and Sebastian, 4, together and be co-parents.

In 2020, while on “The Howard Stern Show,” Cooper explained his decision to enlist Maisani, 53, as a second dad.

“If something happens to me or even if something doesn’t happen to me, the more people love my son and are in his life, I’m all for that,” he shared. “My ex is a great guy and it’s good to have two parents, if you can.”

Cooper — whose parents have since passed — added, “I don’t really have a family and so my friends become my family.”