The event will take place at The Mount Hotel in Tettenhall Wood, Wolverhampton, from 10am to 4pm.
Margot, now aged 17 months, was diagnosed with a rare form of leukaemia aged just 14 months.
Her mother Vicki, who is originally from Essington, and father Yaser launched a worldwide appeal to find her perfect bone marrow match.
And earlier this month, they announced the good news a match had been found and Margot would under go treatment.
But Sunday's event is still going ahead as planned.
Margot's story touched the hearts of thousands worldwide and almost 50,000 people contacted Delete Blood Cancer to see if they could be a match for Margot.