Miley Cyrus wants to perform at Gwen Stefani and Blake Shelton’s wedding. The ‘Midnight Sky’ hitmaker has promised to be on her “best behaviour” if she lands the gig as the wedding singer for her musical pals Gwen and Blake, who got engaged in late October after five years together. Miley began speaking to Gwen on Twitter after the ‘Hollaback Girl’ singer responded to a video Miley posted and called the musician “talented”. The 28-year-old star then wrote: “When my hero’s tweet me I get horny. (sic)” Before she later added in a separate tweet: “ALSO @gwenstefani @blakeshelton I’ll be your wedd…