The first celebrity singer to be revealed on Sunday night was presenter and football pundit Chris Kamara – who appeared as Ghost.
Other characters to take to the stage were Otter, Cat and Mouse, Knitting, Jacket Potato, Jellyfish, and Phoenix.
The panel of judges – Mo Gilligan, Davina McCall, Rita Ora and Jonathan Ross – made their ususal wild guesses as to who could be hiding into costumes.
And viewers at home were also keen to have their say on social media, with everybody from Kate Bush to Dawn French suggested.
But the bookies have their own ideas about the secret celebs, according to the Online Betting Guide.
Here’s who they think will be unmasked as Jellyfish and Cat & Mouse.
1. Martin Kemp and Shirley Kemp
Martin and Shirley Kemp are red hot favourites to be the faces underneath the Cat & Mouse outfits. The Spandau Ballet singer and former Eastender has a 50 per cent probability of being unmasked alongside actress wife Shirley - with odds of 1/1. Photo: John Li
2. Emma Bunton and Jade Jones
With odds of 9/2, celebrity couple Emma Bunton and Jade Jones are second favourite to be the voices behind Cat & Mouse. The former Spice Girl and her singer-turned-chef husband have am 18.2 per cent probability of being the secret stars. Photo: Jeff Spicer
3. Tom and Giovanna Fletcher
Another famous couple are in the frame for the true identity of Cat & Mouse are Tom and Giovanna Fletcher. McFly singer Tom is no strager to television talent shows having appeared in Strinctly Come Dancing, while Giovanna won series 20 of I'm a Celebrity...Get Me Out of Here. They have odds of 16/1 - equating to a probability of 14.3 per cent. Photo: Joe Maher
4. Chris and Rosie Ramsey
The last couple in the frame as Cat & Mouse are Chris and Rosie Ramsey. Comedian Chris is another former Strictly Come Dancing contestant and the husband-and-wife team have shown they are comfortable in front of the television cameras together, having hosted their own chat show. The bookies have them as 7/1 to be the feline and rodent duo - a 12.5 per cent probability. Photo: BBC