On 22 September 2006, Williams, in a joint statement with Andrew Lloyd Webber, left The Sound of Music, by mutual agreement.
[13] In the interim Williams played the role of Betty in White Christmas at West Yorkshire Playhouse, Leeds, directed by Nikolai Foster.
In 2017 she played Helen Walsingham in Cameron Mackintosh's new production of Half A Sixpence, with a revised book by Julian Fellowes and score and lyrics by Stiles and Drewe.
From 9 December – 14 January 2017 Williams played the role of Alice Fitzwarren in Dick Whittington at the London Palladium.
[14] In 2022, she played Lily in a one night concert of The Secret Garden at the London Palladium opposite Hadley Fraser as Archibald.
Williams can also be heard singing several guest tracks on the 'Momentous Musicals' album of 2012[21] and the original London cast album of A Spoonful of Sherman[22] as well as featuring as a guest vocalist for Lance Horne on First Things Last and Alexander Bermange for Songs of Wit and Whimsy Williams's career started in television.
"[24] Her film debut came in 2001 playing Kirsty in Steve Coogan's The Parole Officer and she appeared in First Night (2011) with Richard E. Grant and Sarah Brightman.
[28] Williams appeared as a guest vocalist on Michael Ball's Past and Present concert tour, which was filmed for DVD at the Royal Albert Hall.