Some lucky people will be in with a chance of winning a place on the show.
Crowds flocked to the park this evening, Saturday (Apr 7).
People had until 7:45 to register and then get selected to take part.
There will be a competition between Wales and England to see who the eventual winner is.
The person picked out at random was Nia Roberts who wins a trip to Orlando.
Wales were also crowned the sofa challenge winners and Dec quipped ‘They’ll be dancing in the streets of Llanelli tonight” a nod to the late great rugby commentator Bill McClaren.