The Hoopathon is an attempt to break the Guiness World Record for most people Hula Hooping at one time. More than 3,000 are expected to take part on Sunday.
RPM will stage the event, which will take place at 16 Sainsbury's stores across the UK.
Hula Hoops will donate £1 for every donation of £1 or more, made via text or online, using specially branded packs of Hula Hoops.
In January TV personality Ben Fogle and professional hula hooper Marawa from La Clique demonstrated their hooping skills in London's Leicester Square, to promote the event.