After five weeks of training and rehearsing, 27 women (aged between 18 and 44), gym staff and members at David Lloyd Leisure's Eastbourne club, squeezed into a Mini at the David Lloyd Centre - setting the new world record for the Most people crammed into a Mini Cooper, while raising money for Children in Need.
The previous Guinness world record was held by a New York dance club who forced 26 people in to the same car.
Guinness World Records also recognized the world record for the most people crammed into an original FIAT 500, set by 14 students from ESSCA Business School, in Paris, France.
The event took place on Children in Need Day last Friday. The Mini, donated by Chandlers BMW, was brought inside the David Lloyd Club for the challenge.
Dani Maynard, who works at the David Lloyd Club and organised the challenge, said, "No-one really took us seriously when we first said we were going to do it and I don't blame them really. They must have thought I was a ditzy blonde and didn't think we would be able to do it."
The Guinness World Records rules stated that all 27 participants must be at least five feet tall and 18 years old. Most girls were under a size ten with many at a dress size four, six or eight.
The breathtaking feat, which took 13 minutes to complete and raised £1,778 for Children in Need, was achieved after five weeks of training and rehearsing, which included stretching exercises, building people pyramids and hula-hoop challenges.
The Guinness World Records rules state doors and windows must be closed and helpers step away from the car for five seconds to prove the doors remained closed.
Club DL Kids co-ordinator and swimming coach, Dani Maynard, who organised the event, said: "We didn't think we could do it and it was so uncomfortable at the end - I was worried that the last girl would break her legs and there was absolutely no air left in the car.
"We're absolutely delighted that our efforts paid off and we can now call ourselves world record breakers! What makes this even more amazing is that unlike previous holders, who were dancers and cheerleaders, we are real women of all shapes and sizes - just like the Calendar Girls."
David Lloyd Eastbourne general manager Ben Underwood added: "This was no mean feat - what Dani and her group achieved is truly incredible. I am also delighted that their efforts raised so much money for such a good cause."