Lizzie Davidson: Actress, Sister of Kat Sadler, Such Brave Girls

There’s something uniquely charming about watching real-life sisters play sisters on screen. Lizzie Davidson steps into that role alongside her older sister Kat Sadler in BBC Three’s hit sitcom Such Brave Girls, which won a BAFTA for best scripted comedy.

Known television credits: 3 (Such Brave Girls, Death in Paradise, Mitchell and Webb Are Not Helping) · Instagram followers: 10,000 · Sister’s age (Kat Sadler): 31 (as of June 2025) · Co-star with sister: Yes, in Such Brave Girls

The following table summarizes Lizzie Davidson’s key details.

Are Lizzie Davidson and Kat Sadler sisters?

• Yes – they are real‑life sisters (BBC Media Centre (UK broadcaster’s press office))

How are they related?

Lizzie Davidson is the younger sister of Kat Sadler. The Guardian (UK news outlet) confirmed that Kat, 31, frequently runs scripts past her younger sister and co‑star. They play sisters Josie and Billie in Such Brave Girls – a casting that brings their off‑screen bond directly to the screen.

Are they biological sisters?

All available evidence points to them being biological sisters. The exact nature of the sibling relationship (whether they are half‑sisters or full sisters) has not been publicly specified. The BBC Media Centre describes them simply as “real‑life sisters”.

What is their family background?

Little is publicly known about their parents or upbringing. Kat Sadler has not shared detailed family background in interviews. The sitcom itself draws on their shared experiences, but the women keep their private lives largely out of the spotlight.

The implication: Their on-screen chemistry stems from a genuine bond that cannot be replicated.

Why do Kat Sadler and Lizzie Davidson have different surnames?

• They are sisters but do not share a last name – Kat Sadler uses Sadler, while Lizzie Davidson uses Davidson.

What are their surnames?

Kat Sadler’s surname is Sadler; Lizzie Davidson’s is Davidson. No official explanation has been provided. It may be due to professional stage names, marriage, or other personal reasons – but this is speculative, not confirmed.

Why don’t they share a surname?

Neither sister has addressed the discrepancy publicly. The most likely possibilities include: one of them uses a professional name, or they were not raised with the same surname. Without direct comment from the family, this remains an open question.

The pattern: Such privacy is common among emerging actors protecting family details.

What is Lizzie Davidson known for?

• She is best known for her role in Such Brave Girls (BBC Three, 2023) (BBC Media Centre (UK broadcaster’s press office))

Television roles

Lizzie Davidson has three confirmed television credits: Death in Paradise (2011), Such Brave Girls (2023), and Mitchell and Webb Are Not Helping (2025) (IMDb (industry database)). In Such Brave Girls she plays Billie Johnson, the younger sister of Kat Sadler’s character Josie.

Film appearances

No film roles have been publicly listed for Lizzie Davidson. Her work to date is entirely in television.

Theatre work

There is no verified record of theatre performances. Her acting credits are limited to TV, though she may have training or stage experience that hasn’t been documented publicly.

What this means: The momentum from this series will determine her next career move.

How old is Lizzie Davidson?

• Her exact age has not been publicly disclosed.

Date of birth

No reliable source provides Lizzie Davidson’s date of birth. She does not have a Wikipedia page, and her age is not listed on IMDb or other standard databases.

Age

Her sister Kat Sadler is 31 as of 2025 (The Guardian (UK news outlet)). Lizzie is described as the “younger sister,” so she is presumed to be under 31. Without official disclosure, her age remains unknown.

The catch: Without an age, fans cannot even approximate her generation in the industry.

Was Kat Sadler sectioned?

• Kat Sadler has referenced being in a psychiatric ward in an Instagram post (Instagram (personal social media))

What does “sectioned” mean?

Being “sectioned” refers to detention under a section of the Mental Health Act for assessment or treatment. It is a legal term with specific criteria.

What did Kat Sadler say about psychiatric care?

In an Instagram post, the caption included “psych ward” but did not explicitly state she was sectioned under the Mental Health Act. The topic is central to Such Brave Girls, which explores mental health themes through dark comedy. The Guardian article notes that the show “deals with themes of mental health and family dysfunction.”

The pattern: The show blurs life and art, making the distinction intentionally unclear.

What the evidence says

Confirmed facts

• Lizzie Davidson is the younger sister of Kat Sadler – confirmed by The Guardian (UK news outlet) and BBC Media Centre (UK broadcaster’s press office)
• She appears in Such Brave Girls, Death in Paradise, and Mitchell and Webb Are Not Helping – Wikipedia (community‑edited encyclopedia)
• Her Instagram account has 10,000 followers – Instagram (personal social media)
• Such Brave Girls won a BAFTA for best scripted comedy – The Guardian (UK news outlet)

What remains unclear

• Exact age of Lizzie Davidson
• Whether she and Kat Sadler are half‑sisters or full sisters
• Reason for different surnames
• Whether Kat Sadler was formally sectioned

“The 31-year-old frequently runs the scripts past her younger sister and co-star Lizzie Davidson.”

— The Guardian (UK news outlet)

“I’m going to push even more boundaries this time around.”

— Kat Sadler, quoted in Chortle (UK comedy news site)

What this means for viewers

Lizzie Davidson is an emerging talent whose career is still taking shape. Her close relationship with Kat Sadler gives Such Brave Girls an authenticity that resonates with audiences. The show’s BAFTA win signals that the sibling duo has tapped into something real – a comedy rooted in lived experience. For viewers, the takeaway is that Davidson’s on‑screen charm is not just acting; it is a genuine family dynamic translated to television. As the second series streams on BBC Three and iPlayer, the question is how far this sister act can go. For the BBC, the gamble on a small, personal sitcom has paid off. For Lizzie Davidson, the next step is clear: build on this momentum, or risk remaining a footnote to her sister’s success.