1993–2007: EastEnders and theatre work In April 1993, Cassidy appeared in a production of ''
The Beggar's Opera at Barbican Theatre, London. In December 1993, she joined the cast of the BBC soap opera EastEnders'' as
Sonia Jackson, the youngest daughter of the
Jackson family. Known for playing the
trumpet as a child, her character's key storylines involved her surprise pregnancy which resulted in her giving birth to a daughter
Rebecca, aged 15, whom she gives up for adoption, and later kidnaps before regaining custody after the death of her adoptive parents, the death of her fiancé
Jamie Mitchell (
Jack Ryder), her marriage, divorce and re-marriage to
Martin Fowler (
James Alexandrou), her lesbian affair with
Naomi Julien (
Petra Letang) and feud with her mother-in-law
Pauline Fowler (
Wendy Richard), who's murder she was falsely arrested for. Her initial stint in the soap lasted 13 years, when in April 2006, the
BBC announced Cassidy's departure with her final scenes airing in February 2007. Cassidy also fronted a series
Natalie Cassidy Goes Wild in Australia and played a rival to
Lauren Cooper in an episode of the
BBC Two comedy sketch series
The Catherine Tate Show. Following her departure from
EastEnders, she began working in theatre, appearing in the UK tours of
The Vagina Monologues,
Bedroom Farce and ''Gertrude's Secret
, as well as a run of The Cherry Orchard at the Chichester Festival Theatre. Towards the end of 2007, Cassidy made headlines after losing a considerable amount of weight, and released a fitness DVD titled Natalie Cassidy's Then and Now Workout''.
2008–present: Other work and EastEnders returns In 2008, she starred in the
BBC Three documentary ''Natalie Cassidy's Diet Secrets''. She was also a regular panellist on
Five's
The Wright Stuff and appeared in
BBC Radio 4 play
Blithe Spirit. Later that year, she again gained press coverage for giving up her diet and regaining weight. In 2009, Cassidy was cast in a supporting role in the BBC Two comedy television series
Psychoville, alongside
Dawn French and
Eileen Atkins and fronted the series ''Natalie Cassidy's Real Britain''. She also provided the voice-over for BBC Three's
Underage and Pregnant. In August 2009, Cassidy was announced as a contestant on the
seventh series of
Strictly Come Dancing. She was partnered with professional
Vincent Simone and the pair were the eleventh couple to be eliminated from the competition, finishing in fifth place. In October 2009, it was announced that Cassidy would reprise her role as Sonia in
EastEnders in 2010. She returned to the soap for a short stint in February 2010, in episodes surrounding the wedding of her on-screen sister
Bianca Jackson (
Patsy Palmer) and
Ricky Butcher (
Sid Owen). Cassidy would return to the role again a year later for a single episode in January 2011. In 2010,
E4 announced that they would produce Cassidy's own reality show,
Natalie Cassidy: Becoming Mum. In January 2012, she entered the
Celebrity Big Brother house to appear as a housemate on the
ninth series. She became the fifth housemate to be evicted on Day 16. Cassidy subsequently became the host of
The Health Lottery, a competition broadcast on
Channel 5. In October 2013, it was announced that Cassidy would be making a permanent return to
EastEnders the following year. She appeared in
Jack and the Beanstalk at the Thameside Theatre in Grays, Essex before returning in January 2014, alongside the character's daughter Bex, now played by
Jasmine Armfield. Following her return, her storylines included her divorce from Martin (later played by
James Bye), coming out as
bisexual, a cancer scare, and a relationship with
Tina Carter (
Luisa Bradshaw-White). In August 2020, Cassidy appeared in the BBC comedy series
Mandy. She also guest-starred in a 2021 episode of the BBC sitcom
Motherland. In 2024, Cassidy began hosting her own podcast
Life with Nat, as well as
Off the Telly with
Joanna Page which ran until the following year. She also took part in
The Great Christmas Bake Off. In January 2025, she competed in the
sixth series of
The Masked Singer as "Bush", reaching the semi-final. The same month it was announced that Cassidy would again be leaving her role as Sonia in
EastEnders, following the conclusion of a storyline which saw her enter a relationship with
Reiss Colwell (
Jonny Freeman), whom she later discovers is married to
Debbie Colwell (Jenny Meier), a woman in a coma. Reiss later used money required for Debbie's care to pay for the couple's IVF treatment, before murdering her, which Sonia was wrongly imprisoned for. After being released and discovering the truth, the character gave birth to a daughter in the Queen Victoria pub during the explosion as part of the
40th anniversary celebrations, which results in the deaths of Reiss and Martin. She departed in April 2025. She also appeared in an episode of the BBC comedy series
Boarders. Later that year, Cassidy began fronting the consumer affairs programme ''What's the Big Deal: Britain's Best Buys
for Channel 4, and took part in the fifth series of the ITV competition Cooking with the Stars, ultimately winning the series. In October 2025, Cassidy released her autobiography Happy Days
and embarked on a book tour, as well her own show An Evening with Natalie Cassidy
at Holroyd Community Theatre. She is also set to front a BBC series Natalie Cassidy Learning to Care'' in which she trains to be carer. ==In popular culture==