The calendar, modelled on the Yorkshire Women's Institute's original nude fund-raising venture, has been worked into the script for the popular Welsh-language nightly series.
The calendar is also available to the public at a cost of £4.50, with the profits going to this year's BBC Children in Need appeal.
In the show, the calendar is the idea of the character Cassie, who sees it as a way of gaining publicity for the local brewery run by her lover Hywel and her son Steffan.
She is the first of the charactersto appear in a revealing pose on the calendar.
She persuades other local businesses in the fictional west Wales village of Cwmderi to take part, although Hywel has reservations.
Steffan is also particularly wary of the enterprise as his mother and grandmother are also appearing nude.
Sue Roderick, who plays the part of Cassie, said: "Having the picture taken was a very different experience.
"It was before nine int he morning, pouring with rain, and it was cold. But it was a lot of fun, and it's good for the series.
'Enjoyed the experience'
"But I never thought I would be doing anything like this on Pobol y Cwm!
"I'm sure Cassie has enjoyed the experience, especially as her mother has joined in the fun.
"And who knows? Perhaps this will be a new career for her - she can give up the chip shop and become a middle-aged model."
Siān Eleri Jones, one of the Pobol y Cwm editorial team, thought up the idea for the calendar, which will result in characters like Cassie, Kath, Stacey, Denzil, Darren, Derek, Hywel and Steffan, appearing on kitchen walls int he new year.
Calendars can be ordered by sending a cheque for £4.50, payable to BBC Wales, Pobol y Cwm Calendar, Room C1038A, BBC Wales, Llantrisant Road, Cardiff, CF5 2YQ.