Now a three-piece, Gary Barlow, Mark Owen and Howard Donald will light up the display on the famous shopping street on Sunday, 16 November.
It will mark their first public engagement as a trio.
Jason stunned fans earlier this year when he announced he'd left Take That in order to focus on other projects. He said he'd started to question his future with the band following their record-breaking Progress Tour in 2011.
Fifth member Robbie Williams left in 1996.
Gary, Mark and Howard are now continuing as a three-piece with new album III released on 1 December and new single 'These Days' arriving on 23 November. They will also embark on a mammoth UK tour next year.
In a statement, Take That said: "Turning on the Christmas lights in London is like the starter gun for the main event. It's the official start to the party season. We're really looking forward to flicking the switch on the Regent Street lights next Sunday."
This year's Regent Street lights are themed in honour of upcoming movie Night at the Museum: Secret of the Tomb.
The switch-on extravaganza begins from midday on 16 November, with performances from Union J, Jessie Ware, The Jersey Boys and the Jack Pack. Sadly Take That won't be performing.
Union J's Josh Cuthbert said: "It's such an honour for us to be part of the switch on that will officially launch Christmas across London. We're also really looking forward to performing our new single You Got It All in front of all our fans on the world famous Regent Street."
Heart FM presenters Jamie Theakston and Emma Bunton will host proceedings, with appearances from colleagues including Mark Wright and Jason Donovan.
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