The TV duo returned to ITV1 for a new series of their hit entertainment show Ant & Dec's Saturday Night Takeaway last night, a programme known for its pranks on both viewers and celebrities.
But while fans of the presenters usually find the gags funny and heartwarming, many were horrified by one joke played on a viewer as he waited to become a dad.
In collaboration with Liam's pregnant partner Amy, Ant and Dec secretly played a long-running prank on him in the months leading up to his son Finley's birth.
While some of the jokes were more benign - including getting him to roll around the floor in a prosthetic pregnancy bump at an antenatal class and dressing him as a giant teddy for a photoshoot - viewers were shocked by scenes at a 4D scan clinic.
The sonographer was actually an actor in on the joke with Amy and taking instructions from Ant and Dec, who were sitting in a studio watching as Liam believed he was seeing his unborn child on the screen.
Liam looked happy and emotional as he was fooled into thinking the unborn baby was waving at him and reacting to his voice, while Ant and Dec laughed: "Isn't even his baby."
But viewers thought it was a mean trick, as one tweeted: "Love Ant and Dec’s Saturday Night Takeaway but the baby scan prank wasn’t cool."
— Saturday Night Takeaway (@itvtakeaway) February 25, 2023
Someone else commented: "Anyone else think this is actually quite cruel? This poor man thought this was his baby and it’s not!"
Another person added: "Is it just me or does this feel in really bad taste, messing with a father’s first time experience like this."
While some viewers thought people were being too sensitive, many were offended by the prank which was only revealed to Liam as he sat in the live studio in person on Saturday.
One person tweeted: "And I thought Ant and Dec's career low point was the awful Santander adverts. The baby scan "prank" should have been called out as crass by a member of the production staff when it was first suggested."
Someone else wrote: "Poor bloke probably heartbroken now that his baby didn’t actually wave at him in the scan horrible prank that…Ant and Dec gone down in my estimations."
Another person added: "Bit harsh the guy's thinking he's seeing the face of his child for the first time and ant and Dec are like not even his baby."
There was a sweetener to the punchline, though, as Ant and Dec revealed they had opened a savings account for the baby and would be paying in £1,000 a year until he was 18.
One fan tweeted: "Wowzers Ant and Dec giving that baby 18k is amazing."
Someone else wrote: "Imagine being baby Finley in 18 years time and getting 18k from Ant and Dec."