Carey Mulligan was actually pregnant whilst playing a mother-to-be in 'Spaceman'.

Carey Mulligan stars alongside Adam Sandler in Spaceman

Carey Mulligan stars alongside Adam Sandler in Spaceman

The 38-year-old actress - who is married to Marcus Mumford and already has Evelyn, eight, and five-year-old Winfred with him - gave birth to a little girl last year but explained that whilst filming the role of a pregnant woman in the new Netflix movie whilst she was expecting in real life, some of the time she had to "fake" it and even used the little one for some scenes in the film.

She told MovieWeb: "I was pregnant for some of it and fake pregnant for some of it. When you see my stomach, and I'm lying on the bed with my mother [in the movie], that's my real eight-month baby in there. So yeah, I did channel a lot of motherly stuff."

Carey - who stars alongside Adam Sandler in the film that focuses on an astronaut halfway through his latest mission when he begins to question his life back on Earth - was also required to jump into icy cold water for one scene in the film and recalled that it was a "crazy" day on set.

Adam - who plays her on-screen husband Jakub - joked: "Celine Dion, late at night, when Carey had to dive into a cold pool..."

She said: "It was cold, it was a little crazy... I didn't love it. Johan [Renck, director] wanted me to disappear... run and jump and then dive and then just try and stay under as long as you can... It actually was one of my proudest moments as an actor, staying underwater... Kate Winslet, eat your heart out! How long was it in 'Avatar'? Nine minutes?"