The beloved radio personality, who suffered from a form of dementia, died Sunday at a hospital in Gig Harbor.
Kasem's daughter Kerri publicly battled with his wife Jean over his care in the final days of his life, and following his death she agreed to let her father's widow arrange the funeral.
Kerri and her siblings Mick and Julie, from Kasem's first marriage to Linda Myers, have now confirmed they will hold a separate memorial service to honor the broadcaster.
A spokesman for the siblings says, "Kerri, Mike and Julie Kasem will hold a private memorial service for family and friends on Saturday. We will not give out the location to make sure the ceremony is kept private."
Jean has not yet announced her plans for a funeral or public service. She married Kasem in 1980 and they have a daughter named Liberty.