According to The Sun, the former England defender, who now plays for Burnley, was present for the birth.
Kilner confirmed: “Our precious baby girl is here safe. Speechless with the amount of love we all feel and the joy she’s already brought to our family.”
The couple already have four sons, making this their first daughter. The news comes after a difficult period in their private life, which has attracted significant media attention in recent months.
Walker has previously criticised sections of the press, claiming coverage of his family life went too far and describing Kilner as “a normal girl from Sheffield” who was unfairly targeted alongside their children.
The 35-year-old retired from international football in March after earning 96 caps for England, featuring in five major tournaments from Euro 2016 to Euro 2024.