TV and Radio host Jeremy, who appeared on the 2015 series, has told how the show's judges get an array of stats to help them with their marks.
In a chat on ITV's Lorraine today, Jeremy spilled how Darcey Bussell, Bruno Tonioli, Craig Revel Horwood and former head judge Len Goodman were regularly given figures about rehearsal time put in by the celebs.
And he suggested the judges would mark down those stars who didn't put in the effort.
"I think the judges get information on how many hours you've done during the week," he said. "You can't just skip rehearsals and go out for lunch all the time.
"If they find out they are not impressed."
This year's celebs will have it even harder, with new head judge Shirley Ballas issuing a warning to the contestants.
Originally from Wallasey, Shirley is a former 'British Open to the World' Champion, European, German, United Kingdom, United States and International Latin American Champion.
She was confirmed as Strictly's new head judge earlier this year, replacing Len who stood down after a decade on the show last series.
Now gearing up for her first show, Shirley has given this year's all star contestants a strong warning.
She told the BBC: "If I ask [the celebrities] to do something and they don't deliver it the following week, I'm not going to tell them that it's okay.
"I'm not that kind of judge. I will be expecting things from them and I hope that they will be expecting things from me, to be as honest and as forthright as I can [and] help them become the best dancer they can be."
Strictly Come Dancing 2017 begins this Saturday night on BBC One from 7PM.