12 things we discovered about ‘Harry Potter’ after watching ‘Return to Hogwarts’ special

Like looking through a Pensieve, Potterheads everywhere relived the magic of the “Harry Potter” films on New Year’s Day, only this time, flasks of memories were brought by the franchise’s stellar cast and directors as they came together to celebrate the 20th anniversary of this cinematic wizarding world with a special titled “Harry Potter 20th Anniversary: Return to Hogwarts.”

Nostalgia, of course, is inevitable during reunions, and even the now-legendary wizards of Hogwarts were not immune to its charms. Through archival footage shown in the middle of a friendly, fireside chat, some of the main cast members of the “Harry Potter” films shared behind-the-scenes stories and trivia previously unheard of by fans.

If you haven’t seen this special yet, this is the perfect time to stop reading and go streaming (on HBO Max).

*SPOILER ALERT*

But if you’ve already enjoyed that magical moment, take a look at what we think were some of the most interesting details discussed in that 20th anniversary special.

1. J.K. Rowling had to write a Quidditch rule book for the filmmakers to work on in the "Sorcerer’s Stone."

2. Jason Isaacs, who portrayed Lucius Malfoy, originally auditioned to play Gilderoy Lockhart.

3. In the last moments of the “Chamber of Secrets,” Isaacs mimed kicking Dobby and hitting him on the head with his cane, and director Chris Columbus thought the actor made a mistake.

4. The late Richard Harris — the OG Albus Dumbledore — thought Fawkes the phoenix on the set was real.

5. Alan Rickman knew what will happen in the end. In the special, Daniel Radcliffe revealed to the “Prisoner of Azkaban” star Gary Oldman (Sirius Black) that Rickman learned how the franchise will end from the author herself. The “Prisoner of Azkaban” was released in 2004 while the last book of the novel series was completed by Rowling in 2006.

6. Mike Newell, director of the “Goblet of Fire,” almost broke a rib after rehearsing the Weasley twin’s scuffle with actor James Phelps, who played Fred Weasley.

7. Prior to witnessing Ron Weasley dance with Professor McGonagall in the “Goblet of Fire,” actors James and Oliver Phelps (Weasley twins) played with Rupert Grint (Ron) and told him they have been rehearsing a dance for weeks to put pressure on him.

8. Emma Watson (Hermione Granger) and Tom Felton (Draco Malfoy) had a special bond during the filming of the series. Felton shared that he became protective of her and heard back then that the actress has a crush on him. While Watson confessed that it was an “exciting day” whenever she would be shooting with the actor. It should be noted as well that the two shared the spotlight during their audition. In the end, Emma said that no romantic relationship happened between them.

9. Radcliffe wrote a funny letter to Helena Bonham Carter (Bellatrix Lestrange) when he was 17. The letter says “Dear HBC, It was a pleasure being your co-star and coaster in the sense that I always ended up holding your coffee. I do love you and I just wish I had been born 10 years earlier, I might have been in with a chance. Lots of love and thanks for being cool.”

10. Watson considered leaving the franchise. “The fame thing had finally hit home in a big way," she said. While the actress has spoken about it in the past, it was the first time she talked about it with her co-stars through the special.

11. Watson also had a hamster on the set, who sadly died. R.I.P., MIllie the hamster.

12. Among the last scenes the main trio of the “Harry Potter” films shot was their escape from Ministry of Magic headquarters, where they jump into the floo network. The actors described it as metaphorical, “jumping into the mat to travel into another world,” marking the end of their journey in the Wizarding World.

Watch the trailer of “Harry Potter 20th Anniversary: Return to Hogwarts” special here: