A MYSTERIOUS time-travelling Doctor, who gained hundreds of followers online in his search for his lost Tardis around South Wales, has been revealed to be part of a marketing campaign to promote Wales' historic sites.

For two weeks someone claiming to be television icon Doctor Who has been posting pictures of himself on Twitter and Facebook visiting monuments including Caerleon amphitheatre, and Chepstow and Caerphilly Castles, in a quest to find his missing time machine.

Cadw, the Welsh Government’s historic environment service, revealed the Doctor as Matt Smith lookalike Matt Elliot, a graphic designer from Bristol, in a 90-second video that shows him exploring Wales’s heritage.

The video ends with the line: "You don’t need a Tardis to explore 6,000 years of history in Wales."

John Griffiths, the Welsh minister for culture of sport said the stunt had been "a great way to reach new audiences" who may not have considered visiting a Cadw site before.

Welsh celebrities Cerys Matthews, Scott Quinnell and Derek Brockway helped the Doctor to learn Welsh on Twitter.