Izzie and Sam Hurst will be at Hemel Hempstead Leisure Centre where dancers will be taking part in a dance challenge to raise money for a teenager with a brain injury.
The co-founders will hold two sessions on Saturday where people are encouraged to bring good quality clothes to swap.
Dopplle is an app, mainly for students, which was created to reduce textile waste by swapping clothes to give them a new life.
Izzie, a Masters student, said: “After years of buying fashion and trying to find the most sustainable option that works for me, I am excited to share clothes swapping through Dopplle with as many people as possible.”
She added: “Being at university means we are limited in money while still wanting to look good, so having a sustainable solution like Dopplle is amazing.”
Sam, a veterinary student, said: “We wanted to reach out and launch first to our local community of Hemel Hempstead. It has given so much to us over the years and we are grateful for the opportunity to give back to the community and the help the planet by providing access to swap shop events like these.”
There will be over 500 items to choose to swap from, with up to 10 items being exchanged per person.
People who register on the app can spend their coins (the Dopplle currency) online after the event.
Jewellery, underwear or damaged and dirty items will not be accepted.