JK Rowling wasn't at the Harry Potter premiere because of family illness - but Goblet of Fire was screened for her last week and apparently she loved it!
The producer, David Heyman, told CBBC Newsround: "She gave me a long list of things that she loved and said the films were getting better and better."
The film's director has also revealed details of what to expect from the DVD. Mike Newell said: "Jarvis Cocker and Radiohead play songs which are short in the film, but are in full on the DVD."
He added: "I've done a director's commentary, of course."
David also revealed: "There will be some deleted scenes, how we did certain things, how the effects were done and behind the scenes interviews - probably greater access that we've ever had before."
Asked whether there might be new DVDs of the previous films with commentaries by the other directors, he said: "I think that is something we can look forward to in years to come.
"I don't think it will happen right away, but Chris [Columbus] is very keen and so is Alfonso [Cuaron]."
David is also hard at work on the next film - The Order of the Phoenix.
He said: "We start filming in February. [Director] David Yates has already done a pass through of the entire film in storyboards. He brings a real sensitivity and humanity to the film.
"Luna is a key part. She's someone who's unconventional, a little eccentric, but utterly charming and irrestible.
"Grawp will be a fully digital character, giving him humanity is really important. There's some wonderful stuff with Grawp in the script. I'm really excited about that."
JK Rowling is also being a huge help to the production.
David explained: "In the fifth film we have the Black Family Tapestry. In the book there's a bit of information. But in the film we need to fill that out, and she'll provide us with that information."
He added that - after weeks of speculation that the movie might be filmed abroad - it's definitely being made in the UK.
"We were exploring all the options," he said. "These are expensive films. Ultimately, I'm thrilled we're staying here in Britain."