They’ll all dance at the same time before the judges eliminate them one by one. The first couple eliminated will receive one point, while the second gets two points and so on.
The winner of the Samba-thon is the couple that remains last on the floor, and they’ll receive seven points.
These points are added to the wider scores of the night, so could dramatically impact the scoreboards.
What happened when Strictly last held one?
Strictly’s 2018 dance-a-thon was chaotic, to say the least.
Even the official Strictly account admitted that things didn’t go to plan back then, recently writing on social media: “The last #Strictly dance-a-thon was a hot mess, so it can only get better from here, right?”
Although the show went smoothly, the issue was with the judging afterwards.
Head judge Shirley Ballas’ tablet appeared to freeze, so she couldn’t read the scores as she’d planned - and they had no choice but to resort to pen and paper.
Ballas then named Ashley Roberts and Pasha Kovalev first - even though she was actually meant to be saying who came last in the competition.
Other blunders followed, but the team originally managed to iron things out. Let’s hope this year’s rendition goes a little more smoothly.