Image caption Ioan Gruffudd in Tenby, where his relative may have carried out WW2 exercises

Hollywood actor Ioan Gruffudd has discovered he is a direct descendant of Edward I, the king who conquered Wales.

In a programme tracing the Welsh star's ancestry, he learns his family stretches back to the Plantagenets, including Henry III, Edward's father.

Henry had granted Llywelyn, the last prince of Wales, his title, while Edward was the person responsible for his death.

Gruffudd told the Coming Home programme it was a "stunning revelation".

The Cardiff-born actor returned to Wales from his home in Los Angeles to make the programme with BBC Wales.

He is descended directly from Edward on one branch of his family, and from another son of Henry III on the other.

He said of the discovery: "When one is raised in Wales and most specifically through the Welsh language, we are educated that Llywelyn was the last true prince of Wales, so that has big significance to me personally from what I learned as a child.

"There is a direct conflict that he [Edward] was related to the king of England who made the treaty with Llywelyn, who gave birth to the man who conquered Wales.

"It's a stunning revelation that I'm descended from someone who wanted to cause so much ill to the Welsh and the Welsh history, and who wanted all the power and the control to himself.

"Something to digest on my journey home, something quite significant."

Image caption Kidwelly Castle was well known to Gruffudd's ancestors in the town, the Mansell family

Historians have suggested there may be millions of legitimate or illegitimate descendants of British royalty living in the UK.

Gruffudd also found moving stories of relatives who served in both world wars.

One of his uncles, David Leslie Griffiths, was lost during the Normandy landings in World War Two aged 33.

"These young men and women never had a chance," he said.

"Hearing these personal stories, even from a few generations ago, just goes to show we've all come from that and we've all benefited from those sacrifices."

Coming Home is broadcast on Wednesday 21 December on BBC One Wales at 21.00 GMT