Professor Mary Beard has revealed she posed for life drawings in an attempt to "democratise the nude".
The 65-year-old broadcaster is presenting a BBC documentary about nudity in Western art and its "power to provoke ideas about gender, sex and moral transgression".
As part of the programme, Prof Beard, a classicist at the University of Cambridge, stripped down and posed for the artist Catherine Goodman.
Explaining her decision to bare all, Prof Beard said she wanted to strike back against idealised body images.
"I didn't want to be the elderly academic commentator who talks about an edgy subject entirely from the safety of her own leggings and mac," she said.
"I realise that some people are going to say why on earth did she do it?
Shouldn't 65- year-old women keep their clothes on? But that is also part of the point of the whole series. Whose bodies do we see? Whose are deemed 'okay for art'? Don't old people have bodies too?
"In trying to democratise the nude a bit, and in being a bit more inclusive of different body types - maybe we are striking a little blow against all those idealised, photo-shopped body images with which we are surrounded, and which we can never live up to."
Prof Beard posed for a series of charcoal images from Goodman and said relief was one of her first emotions when she saw the finished product.
"I still find it hard to say what I think of the charcoals," she said.
"I was very relieved when I saw them. And I like them. But it is quite interesting to reflect on how difficult it is to identify with them... is it me, or someone else's view of me?
"That was something I hadn't expected to learn, but it fits with what some more experienced models say."