Aside from those who have died since appearing in the films — including Alan Rickman (Severus Snape), Helen McCrory (Narcissa Malfoy), and John Hurt (Mr. Ollivander), among others — many prominent alums of the blockbuster film series simply did not take part.
Here, a rundown of the Harry Potter stars you won't see while watching the reunion — unless you've somehow managed to master a Summoning Charm.
Michael Gambon (Albus Dumbledore)
Warner Bros Michael Gambon as Albus Dumbledore in 'Harry Potter'
One of the most notable absences from the reunion is Michael Gambon, who played Hogwarts Headmaster Albus Dumbledore for the majority of the Potter films. Gambon took over the role following the death of Richard Harris, who played Dumbledore in Sorcerer's Stone and Chamber of Secrets.
Maggie Smith (Minerva McGonagall)
Jaap Buitendijk/Warner Bros. Maggie Smith as Professor McGonagall in 'Harry Potter'
Robert Pattinson (Cedric Diggory)
Murray Close/Warner Bros. Robert Pattinson as Cedric Diggory in 'Harry Potter and the Goblet of Fire'
Twilight fans may recall that Robert Pattinson popped up in Harry Potter and the Goblet of Fire as doomed Hufflepuff Cedric Diggory before taking on the role of Twilight's Edward Cullen. However, he does not pop up in the reunion special.
Julie Walters (Molly Weasley)
warner bros. Julie Walters as Mrs. Weasley in 'Harry Potter'
Despite her onscreen husband Mark Williams appearing in Return to Hogwarts, Julie Walters, who played Weasley family matriarch Molly in six of the eight Potter films, does not. While it's unclear exactly why she sat out the reunion, it's worth noting that Walters revealed she would largely retire from acting in 2020, following a previously undisclosed bout of cancer.
David Thewlis (Remus Lupin)
Murray Close/Warner Bros. David Thewlis as Remus Lupin in 'Harry Potter'
Kenneth Branagh (Gilderoy Lockhart)
warner bros. Kenneth Branagh as Gilderoy Lockhart in 'Harry Potter and the Chamber of Secrets'
Return to Hogwarts is a bit scant on Defense Against the Dark Arts professors: Kenneth Branagh, who played the ill-fated Gilderoy Lockhart in Chamber of Secrets, doesn't appear in the reunion either. Perhaps he was a bit busy finishing up and promoting Belfast, his latest, widely praised directorial effort.
Jim Broadbent (Horace Slughorn)
warner bros. Jim Broadbent as Horace Slughorn in 'Harry Potter and the Half-Blood Prince'
That goes for Potions professors, too, with Jim Broadbent also missing from the reunion. The Oscar winner played Horace Slughorn, who took over the post from the late Alan Rickman's Professor Snape in Harry Potter and the Half-Blood Prince.
Warwick Davis (Professor Flitwick/Griphook)
Murray Close/Warner Bros. Warwick Davis as Professor Flitwick in 'Harry Potter'
Warwick Davis appeared throughout the Potter series in various roles, most notably as Charms Professor Filius Flitwick and the goblin Griphook, who helps the central trio break into Gringotts Bank in Deathly Hallows Part 2. He does not, however, appear in Return to Hogwarts.
Harry Melling (Dudley Dursley)
warner bros. Harry Melling (center) as Dudley Dursley in 'Harry Potter'
It's perhaps not surprising that Harry Melling is absent from Return to Hogwarts, as the actor has spent the years since playing Harry's spoiled cousin Dudley mostly glad to distance himself from the role. "I think I was very lucky that I was allowed to move away from Dudley," the Queen's Gambit star told EW in 2020. "When you start as a child actor, I think there are certain stigmas you get from that, and I never really wanted to engage in them. I just wanted to continue doing work."
Fiona Shaw (Petunia Dursley)
warner bros. Richard Griffiths and Fiona Shaw as Vernon and Petunia Dursley in 'Harry Potter'
Brendan Gleeson (Mad-Eye Moody)
warner bros. Brendan Gleeson as Mad-Eye Moody in 'Harry Potter'
Another Defense Against the Dark Arts teacher missing from the special: Brendan Gleeson, who played the eccentric Alastor "Mad-Eye" Moody from the fourth Potter film onwards. Actually, Return to Hogwarts is a completely Gleeson-free affair; Brendan's son Domhnall, who played Bill Weasley in the final two films, does not appear either.
Timothy Spall (Peter Pettigrew)
warner bros. Timothy Spall as Peter 'Wormtail' Pettigrew in 'Harry Potter'
Emma Thompson (Sybill Trelawney)
warner bros. Emma Thompson as Sybill Trelawney in 'Harry Potter'
Emma Thompson gave a relatively brief but memorable performance across several Potter films as Divination Professor Sybill Trelawney, who made the prophecy that bound Harry's fate to Voldemort's. Despite that pivotal role in the series' plot, Thompson's role in the reunion was nonexistent.
David Bradley (Argus Filch)
Everett Collection David Bradley as Argus Filch in 'Harry Potter'
Speaking of brief but memorable performances: David Bradley, who popped up across nearly every HP film as Hogwarts caretaker Argus Filch, did not make a cameo in the reunion.
Katie Leung (Cho Chang)
warner bros. Katie Leung as Cho Chang in 'Harry Potter and the Order of the Phoenix'
What, being Harry Potter's first kiss doesn't merit an invite to the reunion? You won't see Katie Leung, who played Harry's onetime crush Cho Chang, among the many Hogwarts students returning in the special.
Devon Murray (Seamus Finnigan)
warner bros. Devon Murray as Seamus Finnigan in 'Harry Potter'
Nor will you see Devon Murray, who grew up alongside the series' central trio as Harry's Gryffindor classmate Seamus Finnigan. You know Seamus: "I'm half and half. Me dad's a Muggle. Mam's a witch. Bit of a nasty shock for him when he found out."
Returns to Hogwarts is streaming now on HBO Max.
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