Director Adam McKay opened up about his decades of friendship with actor Will Ferrell and how it came to an end.

"I’ve learned some lessons. It’s always hard feelings," McKay told Vanity Fair on Monday. The 53-year-old director goes on to explain how he decided to choose another actor for playing the role of LA Lakers’ former team owner Jerry Buss in an untitled HBO series.

McKay explained how Ferrell was not right for the role.

"The truth is, the way the show was always going to be done, it’s hyperrealistic," the director told the outlet. "And Ferrell just doesn’t look like Jerry Buss, and he’s not that vibe of a Jerry Buss."

Moreover, the director explained how other people involved in the project also noted that Ferrel is a genius but they can't see him doing this role. "It was a bit of a hard discussion," he added.

McKay finalized actor John C. Reilly for the role - which Ferrell wanted to portray being a huge Lakers fan - without informing Ferrell.

"Didn’t want to hurt his feelings. Wanted to be respectful," he added. "I should have called [Ferrell] and I didn’t. And Reilly did, of course, because Reilly, he’s a stand-up guy."

McKay further admitted that he wrote emails to the actor in order to reconnect with him but received no reply. He recalled talking to the actor for the last time when they were splitting their company.

"I said, ‘Well, I mean, we’re splitting up the company,’" McKay recalled. "And he basically was like, ‘Yeah, we are,’ and basically was like, ‘Have a good life.’ And I’m like, ‘F--k, Ferrell’s never going to talk to me again.’ So it ended not well."

The director noted that he could have handled the situation in a better way and saved their 25 years of friendship.

"I f--ked up on how I handled that," McKay revealed. "I should have just done everything by the book. In my head, I was like, ‘We’ll let all this blow over. Six months to a year, we’ll sit down, we’ll laugh about it and go, ‘It’s all business junk, who gives a s--t? We worked together for 25 years. Are we really going to let this go away?’"

McKay created a website "Funny or Die" in 2007 and founded a company named Gary Sanchez Productions in 2006 with Ferrell.

However, after years of working together on various projects including the "Step Brothers" movie, the duo announced in 2019 that they are parting ways professionally.

On the work front, McKay helmed the highly anticipated movie, "Don't Look Up," which is slated to release on Dec. 10 and stars Leonardo DiCaprio, Jennifer Lawrence, Timothée Chalamet, Meryl Streep and Ariana Grande.

Ferrell, on the other hand, will feature in a comedy movie, "Spirited" starring Ryan Reynolds.

Will Ferrell
Pictured: Will Ferrell at the New York premiere of “Zoolander 2” on Feb. 9, 2016. Getty Images