Most of the cast were on hand to talk about the DVD and the Chamber of Secrets.
Columbus said he wasn't quite happy with the trailer for Secrets just yet and wants to make sure he gets it perfect before releasing it.
Chris also talked about the extra scenes on the DVD: "I'm really happy with the extra bits, we wanted to give the fans as much as we could."
Where's Peeves?
"We didn't have time to put Peeves back in the movie," Chris admitted, when asked about the still missing scenes, "Peeves is completely CG and adding him just takes too long."
Back to the launch
The DVD is really hot
Plenty of other celebrities turned out, with one glaring exception.
Daniel Radcliffe, Harry Potter himself, wasn't able to be there because of the strict working rules on young actors.
Emma Watson, Rupert Grint and Robbie Coltrane did their best to fill Dan's shoes, chatting to the press and signing autographs. Even Richard Harris turned up to do his bit.
Hear story
Watch Lizo Mzimba's report
What's on the Potter DVD?
Talk Potter!
I was at the Potter DVD launch
