Writer-creator Steven Knight also confirms Tom Hardy will be back for the next run of episodes.
The fourth series of Peaky Blinders is to start shooting in March.
Series three of the Birmingham-set crime drama debuted on BBC One in May. The channel announced shortly afterwards that it has ordered a fourth and fifth series.
Now writer-creator Steven Knight, who also co-created new BBC drama Taboo, has given fans a progress update.
“I’m very, very excited because I’m just completing [the writing of] Episode 6 of Series 4, which again I think is the best yet,” he told Deadline. “And I’m loving it and it’s not like work, it’s not like a labour, I love doing it, and the boys are coming back and they’re loving the scripts, and we start shooting in March.”
He also confirmed that Tom Hardy will be returning as violent gang leader Alfie Solomons during the new series, saying: “We can’t do it without Alfie.”
As well as two more series, it was recently rumoured that a Peaky Blinders film could be in the works.
The show has also become known for making perfect soundtrack choices with songs by The White Stripes, Royal Blood and PJ Harvey. Actor Cillian Murphy has claimed that David Bowie personally asked to have his music featured in the show.