SHERIDAN Smith had jewelry, including necklaces and bracelets, stolen during a raid on her trailer while filming scenes for a sitcom.
The TV actress, 40, said she was “very upset” by the loss of the items, estimated at several thousand pounds.
She is believed to have been targeted by a gang of thieves dubbed the Movie Takers – who raided big-budget film and TV projects.
Police were called on Thursday night after Sheridan’s trailer on set of new Sky show Rosie Molloy Drops Everything was ransacked in south-west London.
An insider from the filming said: ‘It was a very upsetting incident and everyone involved is shocked – but Sheridan is understandably very hurt.
“Luckily they weren’t hugely expensive items, more like everyday things, but she had left them in her trailer for safety while filming the character and returned to find the place had been flipped. .
“It’s absolutely shameful that these people are doing this.”
The source added that film crews have become increasingly suspicious after incidents on other sets, including a recent high-profile theft of expensive props on the set of Netflix blockbuster The Crown.
The insider said, “The film and TV industry is of course very well protected by security, and almost everyone who works in it tends to know each other, so people feel very safe.
“It’s hard to get on a set without being immediately recognized by someone, so a few incidents in quick succession are very unusual.
“It may be that the same people are targeting sets, knowing that there are high-value items out there.”
A Met Police spokesperson said: “The offense occurred at approximately 11.50pm on May 5.
“Jewellery was stolen from caravans in Surbiton.
“There have been no arrests, investigations are continuing.”
In the new show, Sheridan has the lead role of Rosie – a person with anxiety and depression trying to break free from addictions to alcohol, drugs and sex.
A workaholic with a senior career at an accounting firm, Rosie struggles to recover from a spiral of self-destruction brought on by her relentless and stressful workload.
The series is expected to hit the screens in the later part of this year.
It marks a return to comedy for Sheridan, who also appeared in Gavin and Stacey, The Royle Family and Two Pints of Lager and a Packet of Chips.
More recently, she has come to prominence for her hard-hitting dramatic roles in Four Lives, The Moorside and Cilla, as well as her highly acclaimed stage work.