The He's Just Not That Into You star, who is engaged to actor Joey Kern, admits she has been following the Prince's love story with college sweetheart Middleton for a while and she's excited to see them seal their romance when the couple weds at London's Westminster Abbey.
She tells WENN, "I'll be watching 100 per cent. Kate Middleton is our Cinderella. I'm obsessed and enthralled. I'm a big fan. They are a living fairytale those two.
"The little girl in me who always wanted to play a princess is extraordinarily happy that Kate Middleton gets to be one. It's a relationship that has overcome some obstacles that are outside of their control and purely based on love and there's nothing more epic than that."
And Goodwin won't be the only star watching the nuptials - former Beverly Hills, 90210 actress Tori Spelling will be glued to the TV with her husband Dean McDermott.
She says, "We'll definitely be watching. Every woman out there will be watching it. It's the modern day Cinderella. Every little girl dreams of being a princess and Kate Middleton is the every girl. She's making it happen and becoming a real princess. I'll be rooting for her."
Meanwhile, pregnant Kate Hudson is planning to spend the day in front of the small screen with her mother, Goldie Hawn.
She tells WENN, "I can't wait to watch. I can't wait to see her dress and what she's gonna come in on. It's been a while since we've seen a royal wedding. My mum and I have decided to sit at home and watch."
But Hudson, who is dating British rocker Matt Bellamy, confesses she has no real interest in anything royal beyond the big wedding.
She adds: "I don't really follow or am interested in royalty. I don't know what they do anymore..."