Harry Potter stars were called back to the set to re-shoot key scenes, according to reports.
The cast filmed their final scenes for Harry Potter And The Deathly Hallows: Part 2 at London's King's Cross station this April, but the location was recreated at Leavesden Studios in Hertfordshire to shoot some footage again.
A source told The Sun: "They had all said an emotional goodbye to the filming they loved, so it was good news for them as they heard they had to come back."
The newspaper said film bosses wanted to change the way the stars looked in some of the scenes in the second part of the seventh and final Potter adventure.
The world premiere of The Deathly Hallows: Part 1, starring Daniel Radcliffe, Emma Watson and Rupert Grint, took place last month in London.
A Warner Bros spokeswoman confirmed "that the key cast are doing various pick-up shots" but would not reveal which scenes were being filmed again.