Ant and Dec: Which star discovered his great-grandfather was a war hero and which one found out his great-grandfather was a deserter?

Ant and Dec have been delving into their family history and what they’ve discovered about their great-grandparents has shocked one of the Geordie duo.

The TV presenters are known for their tight-knit friendship and shared history as child stars of Byker Grove, pop double act PJ and Duncan, and presenting duties on hit shows including Britain’s Got Talent and I’m a Celebrity.

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But although they were both told in their new family history documentary that their great-grandfathers were in the Army, the similarities ended there.

In forthcoming ITV two-parter Ant & Dec’s DNA Journey, the best mates will get a closer look at their ancestry and what their relatives’ lives were like.

Ant McPartlin will be seen proudly discovering that his great-grandfather was a Battle of the Somme hero, while Dec is shocked to find that his great-grandfather was known as an unreliable drunk.

We’ll see Ant say: “To fight at The Battle of the Somme and to be awarded the Military Medal for Bravery, he was a hero.

"It’s quite emotional. I could have cried . . . you’re so proud.”

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However, as Declan Donnelly is told by a historian that his great-grandfather was court martialled, labelled a deserter, unreliable and a drunk, and sold his gun to get money for his family after enlisting in the Crimean War, his reaction was very different.

Dec said: “Not what I was expecting at all, nowhere near.”

Ant & Dec’s DNA Journey is due to air on ITV in November, when the pals will also return for a new series of I’m a Celebrity...Get Me Out of Here!.

Last year, Ant took a break from the show for the first time in its 18-series run as he went to rehab to address addiction problems, with Holly Willoughby stepping in to co-host with Dec.