Since it debuted on the BBC in 2013, the show, which follows a crime family in Birmingham, England in the 1920s, has become a huge hit - success that has attracted stars like Tom Hardy and Adrien Brody to join the cast.
According to The Guardian, Knight told fans at the recent Legitimate Peaky Blinders Festival in Birmingham that Pitt had asked for a role on the show, and teased his potential involvement.
"We get a lot of people who get in touch and want to take part," he said. "There's Brad Pitt. Snoop Dogg. A$AP Rocky, too. I think in series six we will open the door a little to get some celebrity actors in."
Knight first revealed he was keen to get the "Fight Club" star involved in the show back in 2016, having been informed he is a "Peaky Blinders" devotee, but the actor is yet to appear on the series.
The show's boss did, however, rule out featuring celebrity cameos from stars outside of acting, admitting he finds such cameos "very distracting".
The final episode of "Peaky Blinders"' fifth season airs on BBC One on Sunday, September 22.