For months Ashlee Simpson, 23, and Pete Wentz, 28, of the rock band Fall Out Boy, were laughing off rumors that they were tying the knot, but Wednesday night Ashlee Simpson officially stated they are “happily engaged.” Simpson made the big announcement on her blog: “We know there has been a lot of speculation recently about Pete and I and we wanted our fans to be the first to know, because you guys are the best. Yes, we are thrilled to share that we are happily engaged. Thank you for all of your support and well wishes.” The message continues: “We consider this to be a very private matter, and we wanted to be the first to tell you and to hear it straight from us.” The couple, who have been together since 2006, first started fighting off the rumor last Christmas when Wentz gave Simpson a diamond promise ring. A busy couple, Wentz just launched his fashion line and Simpson has her new album, Bittersweet World. They plan to keep their wedding plans private.