Williams, 66, who played the father of the Weasley family, said: “I love coming back to the wizarding world.”
Oliver Phelps, 40, who starred in the series alongside his twin brother James, added: “Being back on the set reunited with Bonnie and Mark has been absolutely superb – it’s like coming into a time warp, like no time has passed at all since we were last together.”
The reunion also celebrates the launch of the summer feature First Year At Hogwarts – Where The Filmmaking Magic Began at the studios, which gives fans the chance to relive moments from the film.
The exhibition will run at Warner Bros Studio Tour London – The Making of Harry Potter for four months from 7 May.
The feature will allow visitors to relive the famous moment where protagonist Harry experiences the Sorting Hat.
It will also showcase other beloved moments, including Hermione Granger, played by Emma Watson, casting the Petrificus Totalus spell on Neville Longbottom, played by Matthew Lewis, in the Gryffindor common room.