The pair will play neighbours in Mothering Sunday, which is being adapted from the acclaimed novel of the same name by Graham Swift, which you can find on Amazon now.
And they won't be the only high profile actors appearing in the film - with the impressive cast also including Colin Firth and Assassination Nation star Odessa Young.
Birch's screenplay will be directed by Eva Husson, whose previous feature films include Bang Gang (A Modern Love Story) and Girls of the Sun and who has recently directed 3 episodes of the second season of Hanna.
The film is set on Mothering Sunday in 1924 tells the story of a young maid whose affair with an aristocrat comes to an end after seven years.
Speaking to Deadline, director Husson said: "It truly felt like the planets aligned when this wonderful screenplay, Mothering Sunday somehow found its way to me. Alice Birch seemed to whisper in my ear, and I felt everything I'd done so far prepared me for this specific story.
"It was a culmination of all that I'm obsessed with in life: writing, sensuality, and pure cinema. I finished the script in tears, not from sadness, but because it cracked me open, like the most honest works do."
Meanwhile, Colman and O'Connor will be back in action for The Crown season four on Netflix. The highly-anticipated fourth outing for the period drama will show the rise and fall of Thatcher and will introduce Princess Diana.