The comedy, which focuses on a British couple remaking their hit show in America, stars LeBlanc as a version of himself.
Speaking to Zap2It, David Crane and Jeffrey Klarik said: "We thought, 'You know what? If he says no, let's not even do the show'."
However, the duo admitted that they were nervous about pitching the character to LeBlanc.
"It's weird, because we're saying to him, 'You're the punchline'," Klarik said. "We're taking him to lunch and saying, 'We want you because you're the stupidest person they could ever hire."
Crane, who previously worked with LeBlanc on Friends, added: "Initially, he just had to go by blind faith."
Episodes airs on Sundays at 9.30pm on Showtime in the US and on Mondays at 9pm on BBC Two in the UK.