Will Ferrell and Paul Rudd Reveal the Best Part About Working Together (Exclusive)

The friends and co-stars open up to ET at the premiere of their new series, 'The Shrink Next Door.'

Paul Rudd and Will Ferrell have been friends and colleagues for a long time, and that history and connection is serving them well on their latest project, The Shrink Next Door.

ET's Rachel Smith spoke with the actors on the red carpet at the premiere of their new AppleTV+ series at The Morgan Library in New York City on Thursday, and the duo reflected on what makes their working relationship so rewarding and enjoyable.

"I think we have a shared sensibility. We love to make each other laugh," Ferrell explained.

"We do, we love to laugh. And we do, a lot!" Rudd agreed. "Will is just the greatest guy and a terrific actor."

In The Shrink Next Door, Ferrell stars as an anxious, emotionally fragile man who seeks help from a psychiatrist, played by Rudd. Based on a true story, their doctor/patient relationship becomes something darker and more unsettling as the psychiatrist begins to insert himself more and more into his patient's personal life, and manipulate his actions.

"When you spend a lot of time together on a set -- especially on a set like this, where the material can be emotionally taxing -- it's nice to not only enjoy the people you're working with because you admire their talent but to hang out with someone whose company you enjoy. It makes it so much better," Rudd said of Ferrell.

The pair first shared the big screen in 2004's Anchorman: The Legend of Ron Burgundy, and they reprised their roles in Anchorman 2: The Legend Continues in 2013.

However, Rudd joking explained exactly how much they've changed as actors and people in the years since first collaborating.

"We've changed a lot, because we surround ourselves with an army of people that just take care of our every need," Rudd quipped, adding, "Will has three separate sandwich makers!"

"When Paul and I first met, I was 75 pounds heavier," Ferrell joked. "Either 75 or seven pounds heavier, I forget."

Rudd, who also stars in Ant-Man, teased that Ferrell should join him in the Marvel universe. "I mean, Anchorman, Ant-Man, we're only a few different letters away from the title."

Ferrell quipped back, "Just give me the call, I'm waiting by the phone."

The duo's new dark comedy, The Shrink Next Door, premieres Nov. 12 on Apple TV+.