It may have been first thing on a freezing cold morning but the actress – who plays Haley in the comedy – oozed glamour in her pretty blue and yellow dress, embroidered black coat and killer black heels.
Sarah was on Good Morning America to chat about her upcoming movie Vampire Academy, which she filmed in London last year.
"I love it there," she enthused. "It was so beautiful. I love history so even just walking down a random street I'd think, 'This is probably where people died fighting'. I'm very strange and nerdy like that."
Vampire Academy is based on the bestselling supernatural books of the same name.
Sarah said any Modern Family fans who watch the movie might be surprised as her character, Natalie, is the polar opposite of confident, popular Hayley.
"I look very different," she said. "They put fake pimples on me, glasses. I loved it. I got to go to the set and not care what I looked like. She is very geeky."
Sarah, 23, is currently back at work on Modern Family, which is preparing to travel to Australia for an episode this series.
"Modern Family is honestly like a vacation to me," said Sarah. "Hiatus is when I buckle down and work and try to do stuff, then Modern Family is just so much fun. Not that Vampire Academy wasn't fun. Modern Family is just so breezy and everyone loves each other and it's so easy because we've gotten so into the run of it all."
Vampire Academy is currently slated for release in the UK on 23 April.
Watch a trailer for Vampire Academy below: