Demi Lovato shared a photo of herself and boyfriend Wilmer Valderrama from the 2011 wedding of her Sonny With a Chance co-star Tiffany Thornton. But it was much more than a throwback photo, it was a tribute to Thornton's late husband, Chris Carney.Carney, who starred in the short-lived MTV reality show twentyfourseven, was killed in a car accident in Arkansas on Friday. According to Cosmopolitan , the driver of the car — who was also killed in the crash — slammed into a tree after rounding a bend in the road.Lovato posted a photo of Thornton and Carney kissing on their wedding day and as she made clear this was the "perfect example of the love [Carney] shared with Tiffany and how much fun he was to be around.""I've been to many weddings but this is by far the most memorable because the way they looked into each other's eyes and the love they had for one another," Lovato wrote. "There were tons of laughs and tons of tears and I'll never forget the way he looked at her. It doesn't seem real and I'm still in shock.. Still speechless."Adding, "I don't know how to put into words how heartbroken I am for Tiffany and their two baby boys. You're already missed Chris.. And Tiffany I love you so much.. I'm so unbelievably sorry... There are still no words."Lovato also offered a link to a GoFundMe page , which is raising funds towards the "living expenses for Tiffany and their boys KJ and Bentley."