The actor did not appear in the HBO Max special (Picture: Warner Bros.)
The 58-year-old actor, known for playing Professor Lupin in the films, did not return to appear alongside the likes of Daniel Radcliffe, Emma Watson, and Rupert Grint in the programme.
David had a lighthearted approach to his explanation, joking that he was ‘banned’ from appearing because of a backlash from fans over an Instagram post last year.
Posting a humorous explanation, he wrote: ‘Well, last year, as some of you may recall, I foolishly posted what I thought was an amusing picture of a Lupin action figure to which I had attached some comically large feet.
‘It seems I did this on a sensitive anniversary, upsetting many.’
He went on to say: ‘This led to an enormous number of fans (and some cast members) taking to the streets in protest and signing a petition demanding that I be banned from any future Potter celebrations.’
The actor posted an explanation of sorts (Picture: Dave J Hogan/Getty Images)
‘In my defense, it was my wife’s idea. I did not realize the significance of the date, and following the advice of my legal team, the post has since been removed. I hope that has cleared things up.’
So, while there was no official explanation given for his absence, it looks like he’s taken the whole thing in good humour.
While the actor didn’t appear in the reunion special, the likes of Tom Felton, Gary Oldman, Helena Bonham Carter and Ralph Fiennes did all reflect on their times behind the scenes.
They all welcomed us back to Hogwarts in the special episode, telling behind-the-scenes stories and remembering stars of the franchise who we’ve lost over the years.
Eagle-eyed fans quickly spotted some pretty huge mistakes in the HBO episode and alerted the streaming giant to the errors – including an image of Emma Roberts used in error and a mix-up between the Weasley twins.
The mistakes have now been corrected, with producers saying: ‘Well spotted Harry Potter fans!
‘You brought an editing mistake of a mislabeled photograph to our attention. New version is up now.’
Harry Potter 20th Anniversary: Return to Hogwarts is available to watch on HBO Max and Sky Showcase