It's finally here!

Daniel Radcliffe, Emma Watson and Rupert Grint have rejoined the Wizarding World in the full trailer for The Harry Potter 20th Anniversary Reunion. Potterheads will be delighted on New Year's Day as their favourite cast members reunite in what looks set to be an emotional show. The new trailer shows the actors taking a look back on the making of the films and reminiscing about their favourite moments. Here are five things we learned from watching the trailer. https://twitter.com/IGN/status/1473156596830253059 More of the cast are returning We know from the poster that several other cast members will be returning, but now we've been given a glimpse of even more familiar faces in action. The star-studded line up includes Helena Bonham Carter (Bellatrix LeStrange), Robbie Coltrane (Hagrid), Tom Felton (Draco Malfoy), Matthew Lewis (Neville Longbottom), Bonnie Wright (Ginnie Weasley), and Ralph Fiennes (Voldemort) - among others. Filmmakers Chris Columbus, David Heyman, Alfonso Cuarón, Mike Newell and David Yates will also appear. The cast are truly happy to be back The trailer shows cast members laughing, dancing, hugging and looking genuinely happy to be re-uniting. "It feels like no time has passed - and loads of time has passed," Emma can be heard saying as she rushes towards Tom Felton to hug him. "This is the perfect time to sit down with everyone and reminisce," Rupert tells the camera. "There's something so joyous about seeing everyone," Daniel adds. The trio will always have a super strong bond  Daniel, Emma and Rupert grew up making the films together, sharing numerous life-changing memories, so it's no surprise that they have always remained close. But one particular moment between Emma and Rupert  has fans in tears. Sitting in the Gryffindor common room, Rupert takes Emma's hand and says: "It's a strong bond that we'll always have." He then pulls her in for a hug. "We're family, and we'll always be part of each other's lives," adds Daniel. Heart = melted. Helena Bonham Carter still has Bellatrix's rotten teeth Chatting about her favourite part of playing the evil death eater - when she had to pretend to be Hermione - Helena whipped out the teeth her character wore. "I've still got the teeth!" she says before taking them out of her pocket and putting them in. Daniel has realised Harry Potter isn't over In the trailer, Daniel admits that when he finished the last movie, he felt like he was leaving a huge part of his life behind forever. "The implication that the most meaningful thing in our life was done" had scared him, but now, seeing everyone at the reunion made him realise the story never really ended. "It wasn't though!" he exclaims. Roll on New Year's Day!