Kelly Clarkson will marry Brandon Blackstock on October 20, 2013 in Nashville, Tennessee and Blake Shelton will officiate the ceremony.The 'Stronger' singer - who got engaged to the music manager in December - sent out their Save the Date invitations in recent days, and will tie the knot in Nashville, Tennessee.The simple yellow and brown stationary, obtained by gossip website RadarOnline.com, reads: "Bookmark the date for the wedding of Kelly and Brandon," including the date and location saying, "Formal invitation to follow."Blake Shelton, who is managed by Brandon and is one of Kelly's best pals, will officiate the ceremony.The 30-year-old 'American Idol' winner recently admitted that she was "overwhelmed" by her wedding plans because she was struggling to keep their guest-list under control.She explained: "We're just kind of overwhelmed with the planning of the wedding. We're actually thinking fall this year and we're thinking outside. We're trying to make it small, but it is hard. I literally had a breakdown two weeks ago about the wedding list."I'm terrified of everyone watching me walk down the aisle."The singer previously called her relationship her "best accomplishment" after years of being unlucky in love.She said: "I completely fell in love. I did! Welcome to, Cheeseville! I don't know. Your priorities kind of shift and you become happier and all that stuff. It's probably my best accomplishment because I think, for me, especially, I just didn't think it would happen."