Best Interests cast: who stars in BBC One drama with Sharon Horgan, Michael Sheen, and Niamh Moriarty?

Best Interests, a new drama from His Dark Materials writer Jack Thorne, is coming to BBC One this month. The series, which stars Good Omens’ Michael Sheen and Bad Sisters’ Sharon Horgan, follows a family drawn into a complex legal battle over their daughter’s right to die.

Like many of Jack Thorne’s previous dramas, Best Interests commands a high-profile cast, with Sheen and Horgan joined by stars from series like Conversations with Friends, Am I Being Unreasonable, Happy Valley, Somewhere Boy, and more. 

Here’s everything you need to know about the cast of Best Interests, from where you recognise them from already to what you should watch them in next.

Sharon Horgan as Nicci

Who do they play in Best Interests? Sharon Horgan plays Nicci, Andrew’s wife and Marnie’s mother. 

Where do I know them from? You’ll know Sharon Horgan as the writer and star of a number of popular comedies, from Channel 4 parenting sitcom Catastrophe to Apple TV+ dark slapstick Bad Sisters. She’s also appeared in supporting roles in things like Netflix’s crime drama anthology Criminal: UK, and Aisling Bea’s sitcom This Way Up.

What should I watch them in next? If you enjoy Horgan’s more dramatic performance here, you might want to check out Together, a film about the early days of lockdown she starred in with James McAvoy. It’s often a (deliberately) uncomfortable watch, but Horgan is fantastic in it. 

Michael Sheen as Andrew

Who do they play in Best Interests? Michael Sheen plays Andrew, Nicci’s husband and Marnie’s father.

Where do I know them from? It might be easier to try and work out where you don’t know him from – Sheen is a prolific actor and a regular in film and television – but in recent years Sheen has appeared in pandemic comedy Staged, Neil Gaiman adaptation Good Omens, and the Wagatha Christie trial dramatisation Vardy v Rooney: A Courtroom Drama.

What should I watch them in next? Not particularly similar to Best Interests, but very good anyway, is Frost/Nixon, the first of several collaborations between Sheen and The Crown creator Peter Morgan. Sheen plays the talk show host who got Nixon to admit to crimes committed during the Watergate scandal. 

Niamh Moriarty as Marnie

Who do they play in Best Interests? Niamh Moriarty plays Marnie, Andrew and Nicci’s daughter. When Marnie’s health deteriorates, the family is drawn into a complex legal battle with her doctors over Marnie’s right to die.

Where do I know them from? Best Interests is Moriarty’s most high-profile acting role to date, though you might also recognise her from Jack Thorne’s adaptation of A Christmas Carol or the short film My Mother’s Shoes.

What should I watch them in next? You might want to keep an eye out for Moriarty’s literal next role, the current in production fantasy film Silver.

Alison Oliver as Katie

Who do they play in Best Interests? Alison Oliver plays Katie, Andrew and Nicci’s eldest daughter and Marnie’s sister.

Where do I know them from? Best Interests is Oliver’s second television role to date, but you might recognise her as the best part of the weaker of BBC Three’s two Sally Rooney adaptations, Conversations with Friends.

What should I watch them in next? You could revisit Conversations with Friends – although, with all due respect to Alison Oliver, why would you want to? Otherwise, keep an eye out for Emerald Fennell’s Talented Mr Ripley-inspired film Saltburn, which is set to feature Oliver’s film debut.

Noma Dumezweni as Dr Samantha Woodham

Who do they play in Best Interests? Noma Dumezweni plays Dr Samantha Woodham, Marnie's long-term pediatrician who has become close with the family over the past seven years.

Where do I know them from? You'll recognise Dumezweni from the Nicole Kidman/Hugh Grant crime drama The Undoing, the science fiction drama Made for Love, and the Netflix true crime drama The Watcher. Dumezweni can next be seen in the live action adaptation of The Little Mermaid, where she plays Queen Selina.

What should I watch them in next? Dumezweni appeared in Hugo Blick's Black Earth Rising, a legal drama about the prosecution of war criminals. It's well-worth a look if you've not seen it before.

Who else stars in Best Interests?

The cast of Best Interests also includes Shane Zaza (Happy Valley) as Fred, Lucian Msamati (Kiri) as Derek, Chizzy Akudolu (Holby City) as Mercy, Lisa McGrillis (Maternal) as Brenda, Mat Fraser (His Dark Materials) as Greg, Jack Morris (Strike) as Tom, and Pippa Haywood (Bodyguard) as Judge Spottiswood among others.

Who writes and directs Best Interests?

Jack Thorne created Best Interests and wrote all four episodes. Thorne is best known for adapting Philip Pullman’s His Dark Materials novels, but you’ll likely also know him from a number of dramas inspired by true stories, including the Grenfell-esque The Accident, coronavirus care home drama Help, and the Saville-inquiry style series National Treasure. If you enjoy Best Interests, you might want to check out Then Barbara Met Alan, a one-off drama Thorne wrote with Genevieve Barr about activists Barbara Lisicki and Alan Holdsworth.

Michael Keillor directed all four episodes of Best Interests. Keillor has previously directed the Hugh Laurie political thriller Roadkill, Channel 4’s historical drama Chimerica, and episodes of the crime dramas Strike and Line of Duty.