Ant McPartlin and Declan Donnelly were emotional as they found out they are distantly related.
The pair have been investigating their ancestry together in ITV’s Ant And Dec’s DNA Journey.
As the show came to a close on Monday, the presenting duo discovered a “DNA cousin match”.
McPartlin was told he carried a unique DNA marker called S660, then Donnelly found out he had it too.
The marker can be traced back to a Viking warrior, whose skeleton was the first found to have it.
“That’s brilliant,” gasped McPartlin as they heard the news.
“Oh my God,” added Donnelly, leading McPartlin to jokingly ask whether he was disappointed.
During the two-part show, viewers heard how the pair’s friendship was tested in the wake of McPartlin’s drink-driving arrest.
It would be like losing a limb if I lost him from my lifeDeclan Donnelly on Ant McPartlin
Filming for the programme began in 2017 but was halted after McPartlin crashed his car in March 2018 while more than twice the alcohol limit, before entering rehab.
The star struggled with a two-year addiction to super-strength painkillers following a knee operation in 2015.
McPartlin said the search through their family trees had brought them even closer.
“He means the world to me,” he said of Donnelly, adding: “I love him.”
Donnelly said he was at his “happiest and most content” when he was working alongside his TV partner.
“It would be like losing a limb if I lost him from my life,” he said.