The size-14 actress, who plays feisty secretary Joan Harris, has refused to slim down despite calls for her to lose weight.

Jackie Stept, the actress’s mother who lives in Los Angeles, said the accolade was “lovely” and proved her daughter’s approach was right.

“I did always encourage her to be herself,” she said after being told of the MP’s comments, adding that she would tell her daughter she had been declared a role model in Britain.

The actress said of her mother: “She was very celebratory of her body. I never heard her once say ‘I feel fat’.”

In May, Hendricks was voted the “Sexiest Woman Alive” by female readers of Esquire magazine, eclipsing her fellow actress Megan Fox and Michelle Obama.

The Liberal Democrat minister cited Hendricks as she criticised the “overexposure” of skinny models, which she said was causing a crisis in “body confidence” among the young. The use of such models, as well as the routine use of airbrushing, meant that girls and women came under “dreadful pressure … to conform to completely unachievable body stereotypes”, she said.

Mrs Featherstone said: “Christina Hendricks is absolutely fabulous.

“We need more of these role models. There is such a sensation when there is a curvy role model. It shouldn’t be so unusual.”

But it is open to debate exactly how closely Hendricks matches the type of role model in mind by the minister, who was herself voted the most fanciable MP. In Mad Men, shown on BBC Four, her character has an affair with a married executive.

Hendricks has put down her popularity among female fans to her character in the series. “They like to see a woman standing up for herself, especially in this atmosphere in 1962. Joan’s sassy. She snaps back.

“Men love her because she’s in touch with her sexuality and femininity. The men in the office can play with her a little bit. They can tease her, and she’s not going to be in the bathroom crying later,” she said.

Hendricks appeared to relish the attention that her 36C breasts had generated. Asked how she felt about them, she responded: “They are fabulous.”

She also gave advice to men in the magazine on how to get women into bed. They should engage in conduct that many feminists would see as outdated, the actress said. “Stand up, open a door, offer a jacket,” she advised. “It makes us feel important.”

Mrs Featherstone plans to meet representatives of the fashion industry later this year and will propose that digitally enhanced images carry a warning so readers know they were altered.