Frozen made a heck load of money, in addition to being one of Disney's best for years, so the sequel is definitely happening. But we haven't heard so much as a whisper of a release date and it turns out there's a good reason for that - none of the voice work has even been recorded yet.
Star Kristen Ball, who plays the part of Anna, spoke to Collider briefly about progress on the project and she confirmed that the script is pretty much finalised and they'll expect to be ready to start recording the dialogue in April 2016. It has been almost two and a half years since the first film released and took the world by storm, so there's a lot of pressure on the follow up to deliver the same mix of charm, comedy and music.
Of course, the script and voice work are just part of what goes in to making a major Disney production. Given that it's still early days and most of the animation still has to be completed it's likely that fans will be waiting quite a while for the sequel to actually arrive in cinemas. We wouldn't expect it until late 2017 at the very earliest, and more likely a Christmas-ish-time date in 2018 at this stage. Let's hope those young fans are still interested six years after the first release.