BBC Antiques Roadshow star gives his backing to Aylesbury based business
Mr Bly, best known for his regular appearances on the BBC Antiques Roadshow and on his own programme, Heirloom, on ITV, is to chair a panel of experts to provide an opinion on the likely sale value of items.
A free specialist service set up by Where To Sell, they will then suggest the best buyer or intermediary to contact first (www.wheretosell.co.uk).
Mr Bly said: "The website provides a much-needed service in an ever-growing demand for help and advice."
Each member of the panel has specialised and current knowledge of the market in one or more categories.
And although the initiative is in its infancy, it already includes books, clocks and watches, furniture, jewellery, motor cars, paintings, porcelain, silver and statues.
Mike Smith, creator of Where To Sell and also the originator of Homesitters, is delighted to have Mr Bly on board.
"We're particularly lucky that John Bly has agreed to help us," he said. "He has a long and distinguished career in antiques, with several years at Sothebys before joining the family business, which had been started by his great grandfather.
"He is a very busy man, and very well respected, so we much appreciate his involvement and his obvious enthusiasm for Where To Sell.
"The business is growing steadily, but increasingly users are asking 'You've given me an excellent list of people who will be interested in my item, but whom should I contact first?'
"Now with John and his colleagues involved we can provide the answer."
Mr Bly is also a Fellow of the Royal Society of Arts, Liveryman of the Worshipful Company of Goldsmiths and quondam chairman of the British Antique Dealers' Association.
As well as his TV work, he has written and edited a number of books on antiques and collecting, as well as writing for several specialist magazines, and lecturing in Britain, Europe and North America.
Where To Sell lists 293 categories of general items and collectibles. Free to the enquirer, the database lists keen purchasers either by distance or readiness to buy.