The 43-year-old presenter joined co-host and best pal Declan Donnelly for the London Palladium auditions and he was greeted with a standing ovation as he walked on stage.
All but two series of Britain's Got Talent have started between April 9 and April 17 and Saturday, April 13 is the only Saturday in 2019 that falls between those dates.
Ant McPartlin and Declan Donnelly, (left) were pictured back to work together for the first time in nearly a year on Friday.
The make-up guru, 42, liked a supportive tweet about the 43-year-old presenter as he got back to work after nearly a year away from TV screens - following his conviction for drink driving and subsequent rehab stint.
Donnelly hosted the series solo during McPartlin's absence. Get Me Out of Here! with Holly Willoughby.
"Oh god, I'm really, really emotional now. I've missed you all". The 42-year-old liked a tweet from a fan that read: "For you to lose your job because of your ex is very unfair and unjust, you're a lovely soul".
Ant McPartlin returns to work with Dec for Britain's Got Talent
Simon Cowell, the show's head judge, said: "Ant welcome back".
Dec subsequently presented I'm A Celebrity.
In March McPartlin was arrested for drink-driving after he crashed his Mini Cooper into two cars in Richmond, Southwest London.
Their reunion marked Ant's first day back at work since he stepped down from all TV commitments after his arrest for drink-driving to re-enter rehab and focus on his recovery.
The incident saw McPartlin put his career on pause having previously checked into rehab back in 2017 with a painkiller addiction.