When approached, Amanda was told that the offer was the “ultimate compliment”, with Philip’s friend James Robertson Justice asking that the actress didn’t take offence to the invitation.
Speaking to the Daily Mail, Amanda revealed that James was one of eight people who had been “selected to help launch the royal males into their future lives”.
She added: “Between them, they had to choose anyone they thought would be suitable to teach Prince Charles about sex, and James had decided that I was suitable.
“He actually said: ‘We don’t really want people who are experienced but on the other hand, well, obviously they have to know the ropes. Frankly, the main thing one needs is a sense of humour and I know you have got that.”
Amanda also revealed that she was promised she’d become a “fixture” if things went well, although not a girlfriend, and no form of “payment” was offered.
However, the former Coronation Street star turned the offer down, explaining: “The one thing that put me off was he suggested I take a pair of khaki shorts to go shooting.
“It was those that did it. I couldn’t imagine me, in my wig and false eyelashes, dressed in khaki shorts striding across the moors. I had this terrible image of having to face the Queen over breakfast. What would she say? ‘So, Amanda, how was it?’
“I also thought that because Charles was so young, it might be a dreadful experience and I might be blamed. I had to say ‘no’.”
Amanda, now 82, publicly came out as bisexual at the age of 67, marrying her long-term partner Hilary Bonner in 2014.