Declan Donnelly is "devastated" after deciding to host Saturday Night Takeaway alone.
Dec will front the show without Ant, who yesterday was charged with drink-driving.
Saturday Night Takeaway's latest episode has been cancelled this weekend, with Ant leaving the show for the rest of the series.
A spokesperson for Ant said on Monday: "Ant has decided to go back into treatment and step down from his current TV commitments. He’s spoken with Dec and ITV and asked for time off for the foreseeable future.
"As such Saturday Night Takeaway will not be going ahead this Saturday.”
Yesterday, Dec announced the remaining two episodes will go ahead without Ant.
He said: "Whilst I never thought I'd be in this position, after much discussion and careful consideration we've decided that the remaining two shows of this series of Saturday Night Takeaway will go ahead.
"We made a promise to take hundreds of deserving winners to Florida to watch the series finale, and we will honour that.
"Everyone at ITV and the Takeaway team feels we owe it to the audience to complete the series."
Posting the message online, Dec signed off simply: "Dec x."
A source has now said that Dec is "totally devastated" after having to make to the decision.
They told The Sun newspaper: "Dec is facing the prospect of having to work on his own – something he simply hasn’t done because they’ve always been a duo. The decision to go ahead with Takeaway was totally Dec’s, and ITV made it clear they’d respect it.
“He feels strongly that a lot was riding on it for a lot of people, but it is incredibly tough for him right now.”
In a statement, ITV said: "ITV can confirm that Saturday Night Takeaway, presented by Declan Donnelly, will return on March 31, and the series finale will be taking place at Universal Orlando Resort in Florida a week later."