During an appearance "The Ellen DeGeneres Show," airing Friday, Ellen inquired about how the former couple has been spotted out together lately.
"You were a couple," Ellen said to Drew. "Then you broke up, but you're together a lot now."
"We're good friends, and we're doing a film this summer," Drew said, noting, "and I think it's very confusing."
Drew and Justin – who have already starred in "He's Just Not That Into You" together – will next be seen in "Going The Distance," about a couple trying to make a long-distance relationship work.
Drew, 34, had Justin, 31, with her during a recent screening of her HBO movie "Grey Gardens," in New York – but only as her friend, she explained.
"Yes, he was at the premiere in New York," Drew told Ellen. "We're dear friends. I guess people find it a little confusing. I totally understand. It seems like, 'What is the deal with them?' but we just adore each other. We're in each other's lives, and we're friends, and we're working together, and we have worked together."
Ellen pressed Drew asking what her reaction would be if she saw Justin out with another woman.
"We're just friends, so we are free to do whatever we want," she said. "I just hope that they are fantastic people, because he's a great guy and he deserves the most happiness."