Harry Potter is celebrating its 20th anniversary this year and is celebrating with a special on HBO and cast reunion. The cast members look excited to be back together and in the special Daniel Radcliffe revealed he had a huge crush on Helena Bonham Carter who played Bellatrix Lestrange in the series. His crush was so strong he even wrote her a love letter when the series ended where he talked about their age difference.

©NICK WALL/HBO MAX

Radcliffe was cast to take on the legendary role of Harry Potter when he was 11 in 2001. They finished filming the franchise in 2011 when Radcliffe was 21 and Carter was 45. The actress was in a relationship with Tim Burton at the time but Radcliffe poured his heart out in the love letter which he reads during the special. ”Dear HBC. It was a pleasure being your costar — and coaster in the sense that I always ended up holding your coffee,” he wrote. “I do love you and I wish I’d just been born 10 years earlier so I might’ve been in with a chance. Lots of love and thanks for being cool.” the letter continued, per PEOPLE.

Radcliffe, who is now 32, also reflected on the “firsts” he had onset of Harry Potter. “My first kiss is connected to someone here. My first girlfriends were here … It all spirals out from the part of the set somewhere,” the actor explained.

Harry Potter 20th Anniversary: Return to Hogwarts will fly onto your screens on Jan. 1 on HBO Max.