It follows Ant returning to rehab after his arrest over a suspected drink-drive crash on Sunday.
Saturday Night Takeaway's latest episode this weekend has already been cancelled, with Ant leaving the show for the rest of the series.
"Ant has decided to go back into treatment and step down from his current TV commitments," a spokesperson for the star said on Monday afternoon. “He has spoken with Dec and ITV today and asked for time off for the foreseeable future."
"As such ‘Saturday Night Takeaway’ will not be going ahead this Saturday."
According to new reports, Ant is set to take at least the rest of the year off.
It means as well as stepping down from Saturday Night Takeaway, he won't appear in the Britain's Got Talent live shows nor I'm A Celebrity in the autumn.
A friend told The Sun newspaper said: “Ant is devastated. He’s obviously very clearly got a problem. He’s not acting rationally and not acting sanely. He’s not in a state of mind to make decisions, he needs serious professional help."
The pal described the situation as a "nightmare" and said Ant would be taking an "extended break from professional work."
They added: “This is a straightforward case of him needing to go away and take as much time as possible.
"We don’t know what form his treatment will take or how long exactly he will be gone, but it is expected to be for the rest of this year.”
ITV said in a statement yesterday it was "reviewing options" for the last episodes of Saturday Night Takeaway.
They said on Monday: “ITV has taken a joint decision with Ant and Dec’s team not to broadcast Saturday Night Takeaway this weekend.
“We will be reviewing options for the last two episodes of the series which would not feature Ant, who is taking time off to seek treatment. We very much hope he gets the help he needs.”