Zach Braff felt "intimidated" by John C. McGinley when they first worked together.
The 51-year-old actor starred alongside John, 66, in Scrubs, the hit TV comedy series, and Zach admits that their on-screen relationship was actually similar to their off-screen relationship.
Zach - who played the part of John 'J.D.' Dorian on the TV show - told Variety‘s Awards Circuit Podcast: "He was a very accomplished actor, and he was someone I looked up to.
"I was definitely intimidated by him, as was JD. And then all these years later, in the intervening years, we’ve become closer friends."
Zach returned for the Scrubs reboot, which premiered earlier this year, and he relished the chance to star alongside John once again.
The actor explained that one scene proved to be particularly emotional for him.
Zach said: "That very special Episode 8 of the revival of Scrubs, it was so moving. The relationship between J.D. and Dr. Cox, and the relationship between Zach and Johnny C. were all mixed up into one.
"So when he was coming to me, tears welling in his eyes, and talking about how much time he could possibly have left, it really hit me a lot harder than I ever could have imagined when I read it.""
Meanwhile, Zach previously admitted to feeling anxious about directing the Scrubs revival episode.
The actor reprised the role of JD for the episode - but Zach felt much more nervous about directing the show than starring in it.
Speaking to People, he shared: "I was nervous directing the pilot. I really wanted to get it right.
"I think that it was important to set the tone, the back-to-reality basics. We're going to have our fantasies, there's definitely comedy, there's definitely drama, but I felt a lot of pressure to make sure that we nailed the tone for the fans, most importantly, and for ourselves, because that was going to really set us on the right course.
“When we finally locked the pilot and everyone was so excited about it, I felt a big exhale of relief because I knew we at least had a good base as a jumping off point."
