An intruder was apprehended while trying to gain access to the set of Ant & Dec's Saturday Night Takeaway.
According to editors at The Sun, initial reports that four men were trying to gain access to ITV's London Television Centre studios shortly after filming ended at 11pm on Saturday sparked security concerns, but the incident later turned out to be a prank.
A spokesperson for ITV told the newspaper, "A youth who attempted to gain access to the London Television Centre, as a prank, at 11pm last night was quickly apprehended by our security team when he triggered an alarm as he climbed an external wall. He did not gain access to our studios, which were not in operation at the time."
Hosts Anthony McPartlin, Declan Donnelly, Stephen Mulhern and Scarlett Moffatt were reportedly on the premises at the time, as were musical guests, Take That bandmembers Gary Barlow, Mark Owen and Howard Donald.
A police van was pictured outside the studio and officers entered the building to interview staff.
The alert comes at a nervous time for Londoners, just days after a terrorist attacker attempted to breach the U.K.'s Houses of Parliament in Westminster on Wednesday.
The attacker used a vehicle to mow down pedestrians on London's Westminster bridge, three of whom died, before attempting to enter Parliament and stabbing a police officer, who died from his injuries. The terrorist was shot dead by security officers.
Happily though Saturday's security alert was not serious and Saturday Night Takeaway's stars and guests were later pictured leaving the studio unharmed.
The popular light entertainment show returned for its 14th series in February, with Saturday's episode the penultimate one of its current run.
Donnelly and McPartlin are possibly the U.K.'s best loved TV hosts, having presented shows including I'm a Celebrity...Get Me Out of Here! and Britain's Got Talent.
In January, they won the National Television Award for Best Entertainment Presenters for the 16th year in a row.