Declan Donnelly has said he feared his friendship with Ant McPartlin was over amid McPartlin's battle with addiction and admits he was "incredibly angry" when his close friend didn't confide in him.
The 44-year-old presenter has revealed how their longtime relationship was "tested" last year when his pal entered rehab following a drink-driving crash.
Following the road collision McPartlin was fined £86,000 and given a 20-month driving ban.
During their upcoming ITV documentary, Ant & Dec's DNA Journey, Donnelly opens up about how McPartlin's secret struggle with addiction affected their friendship.
"It has been a tough couple of years and it has tested the bond we have shared since we were 13."
"I was incredibly angry at the start, so angry. Disappointed that he didn't ever come to me and say 'I am struggling, I need you’ because that is what I would do if the shoe was on the other foot."
"And he never came to me and that hurt me a lot. There was a point where I thought that that was it. There were times where I wasn’t sure it was going to survive."
He added: "Times where you didn't know it needed to survive or you wanted it to survive. All the while he was away I wasn’t sure where his head was at or if he was going to say 'none of this is for me.’
"I didn’t know what he wanted to do and for the first time in 30 years I had to think about what I was going to do and if I was going to go out on my own. The thought of that filled me with fear."
Ant and Dec's DNA Journey sees the much-loved duo on an adventure around Britain as they follow their maternal and paternal bloodlines.
During the documentary, McPartlin also spoke about his battle, and admits returning to TV was "very emotional".
"Our friendship has been tested and we have come through the other end. And I will be forever grateful and thankful for the love we have.
"I thought the public had had enough. I just thought I wouldn't be allowed to do what I love any more, which was a very sad affair," McPartlin said.
"But, you know, coming back and just being back on screen and the affection and love and support that people have shown, has been quite overwhelming and very emotional. I can’t thank people enough."
Ant and Dec's DNA Journey airs on ITV on Sunday November 10 at 9pm.
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