The former Coronation Street star will make her debut when the award-winning show returns for a fifth series next year.
Hewson will play forthright, experienced hotel manager Joyce Temple-Savage, who plans to shake up the Solana resort and make it a four-star hotel, much to the surprise of the regular holidaymakers.
"I am absolutely thrilled about joining Benidorm, I have watched and loved it from the very beginning," the actress said. "I am so excited about being part of such an iconic show and working with an amazing cast."
Hewson added: "My character is so brilliantly written that I can't wait to start filming."
The 60-year-old will also return to Loose Women later this year.
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