"I've got twice the amount of work to do, so we're going to crack on", Dec said, before moving on quickly to explain what tonight's show has in store.
Tonight's show is the first to air since Ant checked into rehab, following his arrest for drink driving last Wednesday.
Show regulars Scarlett Moffatt and Stephen Mulhern will also take on greater presenting roles.
He wrote: "Back in studio today preparing your #SaturdayNightTakeaway for tomorrow night".
"@SamdySonxxxxx posted: "@antanddec @itvtakeaway Dec you did yourself & Ant proud, it was a fabulous but emotional show, keep smiling. looking forward to next week".
Ant became convinced his co-presenter Dec was a mole after talking to Joanna Lumley, who also featured in the series, and gave Dec an almighty telling off.
A source told The Sun newspaper: "Explaining Ant's absence has been the hardest part of planning".
"The bosses are torn in regards to how they can hit the right tone".
"They want to be respectful to people involved in Ant's vehicle accident, while not bringing down the mood of the show. But Dec is professional and is determined to do a good job".
Saturday Night Takeaway will return next weekend for its final episode with Dec hosting solo once again as the production moves to Orlando, Florida, with a plane-load of fans.
'Just want to say a big congratulations to Dec @antanddec fantastic job tonight ant will be so proud of you bro and @ThisisDavina so good to see you on the show tonight x, ' one fan wrote, leading the troops. "Everyone at ITV and the Takeaway team feels we owe it to the audience to complete the series".