The Twilight star and former American Idol contestant announced their engagement in June 2011 following weeks of speculation that they were planning to tie the knot.
Reed told MTV News that McDonald was taking charge of planning their nuptials, saying: "[Paul]'s doing a lot of it, he is. He's, like, taking control. He sits with his computer in between songs and is kind of on a roll with everything."
McDonald recently insisted that Reed is "the one" for him" and admitted that he never would have expected to hit it off with her so immediately.
"It's kind of one of those things you don't expect. Like last year I never would have thought I'd be getting married," he said. "She's the perfect girl. We fit each other, when you know, you know, and she's the one."
Reed and McDonald began dating in April after meeting at the Los Angeles premiere of Red Riding Hood.
Watch Paul McDonald and Nikki Reed's first meeting at the Red Riding Hood premiere below: