Last year Donnelly hosted the live Britain's Got Talent shows solo and was joined by Holly Willoughby for the 2018 series of I'm A Celebrity. Get Me Out of Here! with Holly Willoughby.
He announced he would immediately be taking time out from presenting and was seeking treatment for addiction.
Britain's Got Talent is just the start of Ant's comeback after he stepped down from all his TV commitments for a year after a hard few months.
Ant and Dec have been friends since they met on ITV show, Byker Grove, playing PJ and Duncan in 1989, before forging a successful TV and music career.More news: Beijing rebukes Trudeau for remarks on drug dealer
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Ant and Dec have been nominated in the Best TV category, despite his time off.
McPartlin was suspended from driving for 20 months and received an £86,000 fine after crashing his Mini Cooper while more than two times over the legal drink-driving limit. Get Me of Out Here! as she starred alongside Dec, 43.
Later that year, Ant entered rehab following struggles with a two-year addiction to strong painkillers as a result of a knee operation.
Ant, 43, has been off work since last spring, when he was involved in a vehicle collision in Richmond.
McPartlin will follow-up returning to Britain's Got Talent with work on Saturday Night Takeaway and I'm A Celeb, both of which are expected to return later in the year.