Johnny Depp made a couple's wedding anniversary extra special by buying and signing their champagne on the Eurostar.

The 'Fantastic Beasts: The Crimes of Grindelwald' star had been in Paris, France, over the festive period visiting the Curie Institute Hospital for children, dressed as his 'Pirates of the Caribbean' alter-ego Captain Jack Sparrow, to surprise the young patients.

On his journey back on the high speed train, Depp - who opted for a low key outfit of a chequered shirt, scarf and sunglasses to travel in - was spotted by David King and his wife Roxanne, who sparked up a conversation with the 55-year-old Hollywood star after realising it was in fact him as he was joined by a bodyguard in business class.

Roxanne recalled to The Sun newspaper: ''We couldn't believe it when he walked into the carriage with his security guard. We did a double take ... we sat there for twenty minutes in silence, then my husband went 'Alright Johnny' and the conversation started.

''We told him it was our first wedding anniversary and he got some champagne and insisted on joining us for a drink with his bodyguard ... the two hours flew by and he talked about how he had been at a hospital in Paris and he asked about our daughter.

''Before he got off he signed our champagne bottle box and wished us a happy anniversary and a happy new year.

''He even gave me a hug and posed for pictures. It was a perfect end to the anniversary celebration.''

According to Kent Online, Depp got off the train at Ashford, South East England, and could have been on his way to pay a visit to his cartoonist friend, Ralph Steadman, who lives nearby in Maidstone.

The 'Murder on the Orient Express' actor often makes trips to hospitals to surprise poorly children dressed as Sparrow from the Disney franchise.