It had been rumoured that Robbie may rejoin Gary Barlow, Mark Owen and Howard Donald for a performance on the programme on 25 February (17), but now the news has been confirmed.
As well as performing one of Take That's biggest hits on the show, which is looking for talented singers to appear in a musical based around the group's songs, Robbie will also act as a guest judge alongside Gary, Dannii Minogue and Martin Kemp.
"I’m looking forward to being back with Gary, Mark and Howard on Let It Shine and am excited to be a guest judge for the very special final," he said in a statement.
The track Take That will perform on the evening is being kept under wraps until the final.
It was previously reported Gary was hoping to have a Take That reunion on the final to boost ratings, but he was going to arrange it without former member Jason Orange.
Jason left the group in 2014, saying in a statement he had decided to call time on his songwriting and performing career.
"Jason just isn’t interested now, he has his own life away from Take That," a source told Britain's The Sun newspaper recently. "With him out of the picture, Gary is pouring his energy into making sure their reunion as a four-piece is a huge success and blows the audience away."
While Take That fans are sure to be delighted to see the group as a four-piece again, Robbie's return will only be temporary. The 43-year-old singer released his latest album The Heavy Entertainment Show in November (16), and is hoping the record has what it takes to make his name in America.
Robbie explained to Britain's Daily Star newspaper: "Back in the 1990s when I went out there to promote my album I was not really dealing with fame very well at all... It was when I realised that the more fame I got, the more insane I became.
"So I just stopped as I needed a place where I was not famous... So I just lived over there and nobody knows me. Now I have changed my mind and I really regret it."