I definitely was like, He could play a potential fun character at any point, she tells EW.

I didnt anticipate him for Angies ex.

But creators J.J. Philbin and Elizabeth Meriwether did.

SINGLE PARENTS Episode: Ketchup ADAM BRODY, LEIGHTON MEESTER

Credit: Richard Cartwright/ABC

We were all made up, and we had our hair all wild.

Up to this point, Derek has been kind of this mysterious character, Meester says.

A reveal that is going to drudge up a lot of feelings for Angie, according to Meester.

SINGLE PARENTS Episode: Ketchup ADAM BRODY

Richard Cartwright/ABC

She is probably more intimidated by him than anything, she explains.

Obviously, theres got to be a lot of mixed feelings about the person you once loved.

Whether or not they end up doing okay for themselves.

Theres a lot of that kind of stuff because she sees a reminder of him every day.

Angies been in denial about how much her relationship with Grahams father has affected her, says Meester.

Its made her really become shy when it comes to relationships and opening up and trusting people.

But dont expect Brody to be a permanent addition.

Not that life imitated art in any way while filming.

That would be an awesome way to do couples therapy, Meester says with a laugh.

But just being around Adam, and being on set with him, its fun.

Hes really funny, and I enjoy everything I do with him.

Working with him is just the icing on the cake.

Single Parentsairs Wednesday at 9:30 p.m. on ABC.