Click play to find out how Oliver got his childhood nickname!
You'll know James and Oliver Phelps as the mischievous joke shop owners in Harry Potter, the Weasley twins - but what were they like as 10-year-olds?
The pair revealed to Newsround which hobbies kept them busy as kids and their most embarrassing moments!
Oliver also lets us in on the story behind his childhood nickname - and how it was created thanks to James.
The twins might look identical, but were their school reports the same? Watch the clip to find out...
Harry Potter and the Deathly Hallows Part 1 Blu-ray and DVD is out now on Warner Home Video.