In the article Natalie Abrams published earlier with these pictures, it confirms Dan Payne (who plays Ivo), along with actors playing young Hansel and Gretel are in this pic. I didn't catch it the first time.

It is pretty ironic that both Regina and Zelena have pasts with versions of Hansel and Gretel. I believe Gretel said she and Hansel raised each other, so I'm guessing the dad is dead and Nick holds Zelena responsible, either because she actually killed him or her actions somehow led to his death. Nick isn't using his normal surprise attack with her, he's making it more personal by going after someone she loves, her fiance.