Jenny Agutter has said she would never have cosmetic surgery as she sees no reason to fight looking her real age.
Agutter told Lorraine: "It terrifies me when I see people who've gone through it as it can actually go very wrong. And I'm very squeamish about surgery so I don't want any of that stuff.
"Anyway, you are the age you are. You've earned the lines on your face, whether they go up or down or whatever. You've earned what you've end up with.
"And you are the age you are so I don't see why one needs to fight it."
The former child star plays Bobbie as a grandmother in the new film, inspired by E Nesbitt's novel The Railway Children.
Agutter rose to fame in the 1970 film adaptation of the classic children's novel about three children who move from London to live beside a country railway station, while their father is imprisoned on suspicion of being a spy. She then appeared in a 2000 TV adaptation of The Railway Children, playing the character of Mother.
She said: "It reflects part of one's life, because when I played Mother I remember someone saying to me, 'Why did you do that? We always think of you as Bobbie.'
"But I said I've grown up, why not play the grown-up part?"
The star of The Avengers and Walkabout is currently filming her 12th series of BBC period drama Call The Midwife, in which she plays nun Sister Julienne.
She said: "Sometimes you go, 'It's easy watching'. But it's not comfortable watching. We've dealt with thalidomide, female genital mutilation, backstreet abortions. And we've seen the changes that have happened to the women there, and they're not easy subjects."
Agutter added: "Each year presents new social changes, new changes in medicine and art, this affects this community."
The Railway Children Return — which also stars Sheridan Smith, Tom Courtenay, and John Bradley — sees Agutter back as Bobbie, and is set during World War II. It looks set to retread familiar ground to the beloved original.
It follows three evacuee children — Lily (Beau Gadsdon), Pattie (Eden Hamilton) and Ted (Zac Cudby) Watts — who are sent by their mother from Salford to the Yorkshire village of Oakworth.
Sheridan Smith plays Annie, Bobbie's daughter, who welcomes the evacuees into their home. The children discover injured American soldier Abe (KJ Aikens) hiding out in the railyard at Oakworth Station, and they are thrust into a dangerous quest to assist their new friend who, like them, is a long way from home.
The Railway Children Return opens in cinemas 15 July, 2022.
Watch: Jenny Agutter says its wonderful to be back in The Railway Children Return