Blake Shelton and Gwen Stefani Are Gettin' Hitched!!!

Blake Shelton and Gwen Stefani are tying the knot, and they've hired a renowned wedding planner for the big shindig ... TMZ has learned.

Sources familiar with the situation tell us Blake and Gwen have hired famed celebrity wedding designer, Jerri Woolworth, who has offices in Tennessee and New York. Woolworth has planned events ranging in size from 15 to 15,000 people. She's planned events for the CMAs, the NFL and the NHL.

We don't know if a date has been set.

We tried contacting Woolworth but were told she had "no comment."