Tenby's legendary Boxing Day Swim is set to become even more famous when it features in a supermarket's Christmas TV advert.

The shop giant - understood to be Tesco - is including a festive dip as one of several seasonal scenarios in its festive on-screen promotion.

And today (Friday), filming, with local people as 'extras', will take place on the North Beach to re-create the silly spectacle of the Tenby Boxing Day Swim.

The Tesco tribute, plus five television programmes featuring Tenby, has helped decide the fancy-dress code for this year's swim, which is the 41st in its history.

"We've had Grand Designs, Ironman Wales, Don't Tell The Bride, Mayday Mayday and Tenby 24/7, so we've decided to have a Tenby On TV theme, which will give everyone plenty of scope," said swim chairman Chris Osborne.

"So swimmers might like to come as a lifeboatman, a bride, a construction worker, a fireman, or maybe an Ironperson!

"Tenby has never had such good television coverage in the space of a few months, and it was particularly inspiring to see the Ironman Wales contestants forging through the sea off the North Beach where, of course, our event takes place."

The Tenby Boxing Day Swim takes place on North Beach, Tenby, on Monday, December 26. Fun on the beach begins at 11 am, with a lifeboat launch, dinghy and a canoe races, a crazy raft challenge and fancy dress parade. Swimmers enter the water at 11.30 am and are presented with commemorative medals around a blazing bonfire.

Last year, nearly 400 crazy bathers braved a snowy beach and chilly sea to take part, raising over £11,500 for charity.

This year, the Tenby Sea Swimming Association, which stages the swim, is raising money for Pembrokeshire Cancer Support; bereavement support charity All-Pembrokeshire Cruse;the Welsh domestic abuse charity, Hafan Cymru and the Tinker's Hill Bird of Prey and Swan Rescue Centre.

Swimmers can also collect for their own charities and good causes, and everyone is urged to get themselves sponsored

For more information and to download a sponsor form, visit http://www.tenbyboxingdayswim.co.uk">www.tenbyboxingdayswim.co.uk or the swim's Facebook group.

The event is sponsored by FBM Holidays, Trefloyne Manor, Celvac, Jago and D Js Nightclub.

Anyone who was awarded a trophy after the 2010 swim is asked to return it to the Fourcroft Hotel by December 1.