Piggott was a giant of the saddle, counting nine Derby winners among his Classic haul and being crowned champion jockey 11 times during his long and illustrious career.
Nicknamed the Long Fellow, he was regarded as one of the all-time great jockeys, clocking up a staggering 4,493 victories.
He died aged 86 in Switzerland on May 29, with a private family funeral held the following month.
St Luke's Church in Chelsea will host the service, which starts at 3pm, with the event to be ticketed as it is anticipated more people will wish to attend than the venue can accommodate.
His daughter Maureen Haggas said the memorial event would be a chance to "celebrate his amazing life".
Applications for tickets should be sent via email to LesterPiggott@addeddimension.co.uk, including a postal address and contact telephone number, by September 14.
Postal applications can be sent to: Lester Piggott's Service of Thanksgiving, Added Dimension Events, 19 Redburn Street, London, SW3 4DA.