In the last 12 months Danny Dyer has called David Cameron a “twat” on live television, watched his daughter win Love Island and delivered Channel 4’s Alternative Christmas Message.

Now there may be a simple explanation for the actor’s elevation to national treasure status: he is the descendant of a saint.

The EastEnders actor made the discovery while filming Danny Dyer’s Right Royal Family, which airs on 23 January on BBC One.

Among other revelations, the actor is told that his 26th great-grandfather is the French King Louis IX, a devout religious leader who died in 1270 and was later canonised as Saint Louis.

Dr Emily Guerry, a medieval historian, told Dyer that his distant ancestor at one point wore the robes of a humble monk to lead a procession through Paris honouring the arrival of a religious relic purported to be the crown of thorns worn by Jesus Christ at his crucifixion.

To commemorate his ancestor’s actions, Dyer recreated the walk through the French capital barefoot.

The actor, who has previously established a blood connection to the English rulers William the Conqueror and Edward III, said he was impressed to discover his new relation. “I can be told all sorts of information but to actually walk in King Louis IX’s footsteps, to think that he did this as a king, I admire him because he does exactly as he preaches and is showing everybody. He walked for six miles barefoot, in pain, and that you’ve got to respect. Considering the money and power he had and the life he could have lived, I think it’s very brave. Bless him.”

After being told that Louis was later elevated to sainthood after a series of miracles, Dyer said: “It’s just so much to take in. I’m related to a saint.” He said it was hard to believe sacred blood was “coursing through my veins”.

However, Dyer may not be alone. Dr Adam Rutherford, the author of a book on genes entitled A Brief History of Everyone Who Ever Lived, said the passage of time and overlapping ancestries meant “there is a time in history where all lines of all family trees cross through all people”, meaning many Britons of European ancestry are likely to be descended from Saint Louis.

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Rutherford added: “Every European is descended from every European alive in the 10th century, if they have any living descendants. We know from his royal pedigree that Charlemagne has living descendants (Richard Branson boasted of it, Christopher Lee, too), which means that literally every European is also descended from Charlemagne.

“The basic problem is that we think of family trees fanning out from us into the past, but that means that the number of ancestors we have doubles every generation back. By 1,000 years ago, every person has more ancestors than people who have ever existed.”

Despite this, he said, it was impressive that Dyer had been able to follow his ancestry back this far and prove the connection to the French king.

King Louis IX, who led the seventh crusade to the Middle East, was canonised by Pope Boniface VIII in 1297 and lent his named to many settlements around the world, including the US city of St Louis in Missouri. Dyer has yet to have any settlements named after him, nor has he led an armed intervention in the Holy Land.