Ant and Dec will make a "mind-blowing" discovery that one has royal ancestry.
Ant and Dec
A new ITV two-part special, 'Ant & Dec's DNA Journey', will reveal that one of the TV presenting duo is a descendant of royalty.
Speaking about the show, Ant said: "I'm a bit of a geek when it comes to historical events, so to get the chance to research our family history using our DNA was too good an opportunity to pass up.
"What we find out is mind-blowing and nothing either of us could ever have imagined. It's something that will stay with us both forever."
The pair will travel to Ireland and the US, including the United Nations headquarters, where they will meet relatives they had no idea existed in the flesh.
They will be guided by expert genealogists and historians to explore their maternal and paternal bloodlines.
Dec added: "A huge part of this was to find out my heritage, especially on my dad's side.
"I always thought I knew a fair bit about where I came from but it turns out I was wrong.
"Whilst it was incredible to find out about the past, what was hugely overwhelming was to meet relatives neither of us knew we had. It was a truly amazing experience."
The programme will give viewers a personal glimpse into the pair's relationship, which has spanned nearly three decades.
Siobhan Greene, who commissioned the show, said: "This documentary captured Ant and Dec at an intersection of the lives.
"I feel sure the ITV viewers will be on the edge of their seats watching twists and turns of their DNA journey unfold, and their honesty and openness, will leave a lasting heart print."
Tagged in Declan Donnelly Ant McPartlin