Simmons, 62, and Tweed, 54, will get married on Oct. 1 in Beverly Hills, according to their wedding invitation. Entertainment Tonight first reported the news. The invitation was created by the couple's kids, Nick and Sophie.
The dress code for the ceremony? "Classy Cocktail Attire Requested, although we know some Rockstar attire will be worn."
The new season premieres Tuesday, Oct. 4 on A&E.