This morning King Diamond announced on his website that he and the band will return on stage this year.
On June 9, 2012, they will be playing the Sweden Rock Festival in Sölvesborg (Norje), Sweden. This will be the only show in Scandinavia this year. (Check out this video message directly from King Diamond.)
And the other announced show will take place at Hellfest in Clisson, France on June 15, 2012.
According to the Helfest website these will be the only two European dates this year.