One Day cast: All actors & characters

Daisy Phillipson
Leo Woodall and Ambika Mod as Dexter and Emma in One Day

One Day, the anticipated romantic drama series based on David Nicholls’ book of the same name, has landed on Netflix – here’s everyone you need to know in the cast. 

Netflix has produced a wide range of original series and movies based on books, many of them proving popular thanks to their established fanbases and rich storytelling. Virgin River, Heartstopper, The Chosen One, and Fool Me Once are all famous examples. 

What makes One Day even more intriguing is that Nicholls’ novel was already made into a film – one that didn’t go down too well due to its format. Since the book spans 20 years, it was difficult to fit the storyline into a shorter timeframe in a meaningful way. 

But this has been rectified with Netflix’s iteration, bolstered by impeccable performances from its leads. So, with One Day out now, here’s our rundown of the cast, including the actors and the characters they play. 


One Day cast & characters

Below, you’ll find a list of the core cast and characters in One Day, but before we get into it, here’s the official synopsis: “One Day tells the story of Emma Morley and Dexter Mayhew who, on 15th July 1988, the night of their graduation, speak for the very first time. The next morning, they go their separate ways but where will they be on this one ordinary day the next year, and the year after that, and every year that follows?

“Each episode finds Dex and Em, one year older, on this one particular date, as they grow and change, move together and apart, experience joy and heartbreak. One Day is a decades-spanning love story, based on the worldwide bestseller by David Nicholls.”

Dexter: Leo Woodall

Leo Woodall as Dexter in One Day

Leo Woodall plays Dexter, who on the surface is a rich playboy. But as his relationship with Emma shows, there’s far more depth to this character than meets the eye. 

Speaking to The Hollywood Reporter about taking on a leading role, he said: “I struggled at the beginning of One Day – I was struck by how much pressure I felt being a lead. I didn’t know if I should behave like the captain of a sports team. And I struggled with not having any kind of moment to myself, like you can’t tie your own shoelace or spit your own gum out.”

However, he had a great way to unwind at the end of the day: “Had a gin and tonic and went to bed.”

Woodall is, of course, known for his scene-stealing performance in The White Lotus Season 2. He’s also appeared in Citadel, Vampire Academy, and Cherry. 

Emma: Ambika Mod 

Ambika Mod as Emma in One Day

Ambika Mod plays Emma, the second lead. She’s smart, funny, and a talented writer, but she’s also highly self-deprecating. However, Dex is always around to lift her confidence, even if he annoys her sometimes. 

Speaking on an episode of The Graham Norton Show (via The Huffington Post), Mod explained that she was having a rough time before landing the One Day role, feeling a bit lost during Edinburgh’s Fringe Festival in 2019. 

“On the last day of the Fringe, we climbed Arthur’s Seat and I remember it as a terrible time. I was not loving myself or my life,” she said. If you’ve seen One Day, you’ll remember Dex and Em climbing Arthur’s Seat – the main peak of the group of hills in Edinburgh – in Episode 1.

“Then cut to almost exactly three years later and I am filming in Edinburgh at Arthur’s Seat playing the lead in a Netflix series of my favorite book,” added Mod. “It felt very special. A full circle moment.”

As well as being a comedian, the star’s other acting credits include This is Going to Hurt and I Hate Suzie.

Tilly: Amber Grappy

Amber Grappy as Tilly in One Day

Amber Grappy plays Tilly, Emma’s housemate and best friend, having met during their first year at the University of Edinburgh. 

Grappy is known for Wreck, The Baby, and Smothered. 

Alison: Essie Davis

Essie Davis as Alison in One Day

Essie Davis joins the One Day cast as Alison, Dex’s fun-loving, posh-but-not-snooty mom who only wants the best for her son. 

You may remember Davis for her expert performance in The Babadook. She’s also starred in The White Princess, the Assassin’s Creed movie, and Game of Thrones

Stephen: Tim McInnerny

Tim McInnerny as Stephen in One Day

Tim McInnerny plays Stephen, Alison’s husband and Dex’s father who similarly wants to see his son excel. 

McInnerny has appeared in numerous shows and movies over the years, from Game of Thrones and Severance to Notting Hill and Black Adder. 

Ian: Jonny Weldon

Jonny Weldon as Ian in One Day

Jonny Weldon plays Ian, a wannabe stand-up comedian who Emma ends up dating after they meet while working at a London restaurant together. 

Weldon’s other acting credits include House of the Dragon, Stath Lets Flats, The Outlaws, and Breeders.

Sylvie: Eleanor Tomlinson

Eleanor Tomlinson as Sylvie in One Day

Eleanor Tomlinson joins the One Day cast as Sylvie, Dex’s later girlfriend who is even more privileged than he is – in other words, her family is Saltburn coded.

Tomlinson is known for Jack the Giant Slayer, Poldark, The Outlaws, and the War of the Worlds TV series. 

Helen: Joely Richardson

Joely Richardson as Helen in One Day

Joely Richardson plays Helen, Sylvie’s posh-and-snooty (but not as much as her husband) mother.

Richardson has a wide range of acting accolades to her name, including The Sandman, Nip/Tuck, Thanks for Sharing, and The Patriot. 

Lionel: Toby Stephens

Toby Stephens as Lionel in One Day

Toby Stephens plays Lionel, Sylvie’s cantankerous father. As his character description states, he “comes from very old money – and old ideals.”

Stephens has starred in Die Another Day, The Machine, Jane Eyre, Lost in Space, and Percy Jackson and the Olympians.

That’s everything we know about the cast of One Day, which is available to stream on Netflix now. 

About The Author

Daisy is a Senior TV and Movies Writer at Dexerto. She's a lover of all things macabre, whether that be horror, crime, psychological thrillers or all of the above. After graduating with a Masters in Magazine Journalism, she's gone on to write for Digital Spy, LADbible and Little White Lies. You can contact her on