Russell Wilson & Ciara: Officially Married Before Castle Wedding

It looks like Russell Wilson and Ciara did the deed before they said "I do" ... because we found out they got married before Wednesday's ceremony.

TMZ Sports has learned the couple applied for a marriage certificate in King County, Washington, and it was signed by a judge on July 5th, which officially made them husband and wife ... the day before they walked down the aisle.

The marriage application lists their government names -- Russell Carrington Wilson and Ciara Princess Harris.