Blake Shelton doesn't have any children, but his fiancée, Gwen Stefani, knows that a blood relationship isn't necessary for a man to be a good father.
On Sunday, Gwen posted a tribute to Blake, who turned 45 on Friday, writing, "happy father's day to the most generous patient loving funny guy i know - we love u so much." She also uploaded a series of images of Blake with her three sons -- Apollo, Kingston and Zuma -- whom she shares with her ex-husband, rocker Gavin Rossdale.