Diana Swale, the US actress best known for playing Charlie’s mother Mrs Bucket in the 1971 film Willy Wonka & the Chocolate Factory has died at the age of 88.

In statement on Monday, her representative confirmed that the actress passed away early on Friday morning "with family by her side".

"She was a loving wife, mother, grandmother and friend, and will be dearly missed." The statement said.

Cast of Willy Wonka (L to R) Diana Sowle, Julie Dawn Cole, Peter Ostrum, Michael Bollner, Denise Nickerson and Paris Themmen in Los Angeles in 2014. (Photo by Albert L. Ortega/Getty Images)

Following the death of Gene Wilder, who played the titular sweet factory owner in the movie, Sowle was the last surviving adult star of the classic Roald Dahl adaptation.

In the movie, Sowle memorably sang Cheer up, Charlie.

Sowle ran a free tutoring programme for underprivileged children in her hometown of Washington DC for 23 years.

She also frequently appeared as Mrs Schubert in Shear Madness, one the world’s longest running non-musical plays which next year will celebrate its 40th anniversary. Other screen roles include films Clear And Present Danger, and Guarding Tess.

Remembering Gene Wilder, Sowle said in an interview: "We'd be working on a scene and having a lunch break and he would be coming in to film another scene, and he would join us on a lunch break and we'd have lunch.

"He was so nice, he never acted like, 'Oh I'm a bigger star than the rest of you', he was always friendly and courteous and funny and told nice stories."