Charlotte Cornwell, who starred in Dressing For Breakfast and Rock Follies, said: "Actors have been far too shy about talking about what they earn. Men in particular should come clean."
She was speaking at the launch of a survey which has found that female actors were still paid an average 15 per cent less than their male counterparts a year, despite working 20 per cent more days.
Women earn an average daily fee of pounds 352 in films, pounds 15 less than men; pounds 302 in television, pounds 30 less than men; and pounds 122 in radio, pounds 22 less than men, according to the survey of 373 "middle-range" performers.
The only areas where women were paid more, or about the same, were in theatre and advertising. Women and men both earned pounds 82 a day in the West End of London, while at pounds 48 a day women earned only pounds 4 less than men in repertory. In fringe theatre women earned pounds 42 a day, pounds 9 more than men, while in commercials they earned pounds 1,089 a day on average, pounds 145 more than their male counterparts.
Ms Cornwell, 46, said one way to right the imbalance was for actors to tell each other what they were earning. But when she revealed details of her pay in various productions in the Independent last March, she had had angry calls from agents.
"Agents will never talk about it, but male actors in particular have a duty to talk about what they are being paid - although they are criminally shy about doing so," she said.
The Equity-supported report by Dr Helen Thomas, a senior sociology lecturer at Goldsmiths University, also revealed that women were paid less than men for equivalent parts in all performing media. For a lead role women earned an average pounds 166 a day, pounds 84 less than men. For a "large" support role they earned pounds 178 a day, pounds 37 less than men. But in small support roles they earned pounds 352 a day, pounds 16 more than men.
Part of the reason why the women earn less is that there are fewer lead roles for them and they have to compete with a pool of talent at least as large as the male one. Ms Cornwell said that it was not enough for employers to point to the women's lead parts which had emerged in recent years - such as female prison governors, psychopaths and football managers.
"We want to start encouraging employers to promote work which sees the world through women's eyes. It's a very different point of view and equally valid," she said. Even Hollywood stars such as Susan Sarandon and Jodie Foster suffered from ingrained sexism when it came to pay, she added.
"If you look at leading actresses in Hollywood they have all been paid less ad infinitum than their male counterparts and they've also complained about the roles they've been given."
The Men Behaving Badly actors Caroline Quentin and Lesley Ash recently gained equal pay to the male stars Martin Clunes and Neil Morrissey by threatening to walk out on the successful television series.
8 Unequal Pay For Equal Parts; Goldsmiths University, pounds 7.50.