The 32-year-old actress was wearing just a gold two-piece when she was turned away from the swanky eaterie.
Onlookers said she was mortified after being told she was not dressed appropriately at the Kyma coffee shop at the four-star Waves H๏τel and Spa in Barbados.
But another holidaymaker then spared her blushes and stepped in to lend her a dress.
The sun-seeker told us: “Helen turned up to the Kyma bar with her kids and was enjoying a drink outside. It was seriously H๏τ in the early afternoon and when Helen took her kids indoors to get the air-conditioning, she was told she had to cover up or leave.
“She looked horrified because all she had on was a ʙικιɴι and people were staring. My sister had a Skims black dress and lent it to her so she could go in.
“She was so grateful because it was a little awkward.
“It’s a pretty upmarket bistro-come-cafe, and although you can go there straight from the beach, you have to have a T-shirt or a kaftan on. Helen sat back and enjoyed a coffee with the kids after that.
“She returned the dress — and a pair of flip-flops we lent her — to the H๏τel reception before she left.
“She was a great sport about the whole thing.”
Helen and her three children — Matilda, eight, Delilah, five, and two-year-old Charlie — from her relationship with footballer Scott Sinclair, have been in the Caribbean for the past week. She split from her fiancé Scott last year following 13 years together.
Helen, who played Rosie Webster in Coronation Street for almost two decades before taking a step back in 2018, was back on the box for I’m A Celebrity All Stars earlier this year.
Corrie has kept the door open for a potential return and Helen said she would love to go back to Weatherfield if Rosie had children.