Author and screenwriter Alice Oseman said she “couldn’t believe” Olivia Colman agreed to appear in her Netflix series Heartstopper.

The Oscar-winning actress, 48, appears as Nick’s mum in the drama, which follows the lives of Charlie Spring and Nick Nelson after they meet at school and fall in love.

Oseman, 27, wrote the popular Heartstopper graphic novel series, which has sold one million print copies since its publication.

She previously said a large part of showing realistic experiences comes from authentic casting, and she had been very particular about who would take the roles of Charlie, Nick and the show’s other characters.

Talking about casting Colman in the series, she said: “I was shocked. When we were discussing trying to get a big name to be Nick’s mum, I was literally like, there’s no way this is going to happen.

“This is the silliest idea ever and there’s literally not any point doing this.

“But we tried anyway and Olivia wanted to do it, and I just couldn’t believe it.

“There’s really no other way to say it, I was just shocked but so, so happy, because she’s such an incredible actress, she brings so much to that character, and all the scenes with Nick’s mum just feel so special and subtle and just really beautiful performance.”

Kit Connor
Kit Connor plays Nick in Heartstopper (Ian West/PA)

Joe Locke will make his screen acting debut portraying Charlie, while Nick is played by Kit Connor, who previously played a young Elton John in the singer-songwriter’s biopic Rocketman.

Oseman said Colman “cried” after shooting the coming-out scene with her on-screen son.

She said: “She seemed to really enjoy it. She was only on set for two days and to be honest, I didn’t really get to talk to her very much because we’re on set and it’s very intense.

“But I feel like she really loved the story and she really connected with Kit, who plays Nick, and just really enjoyed working with him.

“I remember when they were rehearsing the coming-out scene she just cried because she thought Kit was so adorable. It was an amazing experience.”

Also in the show are William Gao, who plays Tao Xu, Yasmin Finney as Elle Argent, Corinna Brown as Tara Jones, Kizzy Edgell as Darcy Olsson, Sebastian Croft as Ben Hope, Jenny Walser as Tori Spring and Fisayo Akinade as Mr Ajayi.

Heartstopper launched on Netflix on Friday.