Anthony McCarten thinks 'The Darkest Hour' has set a new benchmark in prosthetics.
The 56-year-old screenwriter wrote the war drama - which follows British Prime Minister Winston Churchill at the beginning of World War II - and has claimed that, due to the prosthetics, it was hard to tell "where Winston starts and Gary Oldman ends".
Speaking exclusively to BANG Showbiz, McCarten said: "Winston Churchill would plonk himself down next to me on the chairs and I would be chatting to him and you wouldn't be able to tell where Winston starts and Gary ends.
"He could be as close as I am to you and look for some hint that it was prosthetic. You couldn't. It's a new benchmark in prosthetics, I think."
The film has been widely praised internationally - being nominated for Best Film at this year's Academy Awards and BAFTAs - and McCarten said he is "very pleased" and "really excited" by the recognition.
He said: "I mean it keeps the film in the spotlight and you know we are making it for the public and the public have embraced it.
"The awards season is just great for putting attention on it and keeping it, you know, in the public mind. We are really excited and very pleased."
Oldman - who won a Golden Globe for his performance - is also up for Best Actor at both award ceremonies, and McCarten said he was "electrifying".
McCarten explained: "Gary is just a pro, a delight, a genius, a creative powerhouse and he endured the ordeal of huge proportion in a whole bunch of areas.
"He would have to be on set at 3am in the morning to undergo three hours of make-up before we started and he just took that without any complaints.
"He was rock solid on his lines, electrifying in his performance and always with a smile on his face."