The Duke of Sussex has filmed a special introduction for 'Thomas & Friends: The Royal Engine'.

Prince Harry is ''proud'' to have been asked to be involved with the special animated project, which has been produced in recognition of the popular children's show 75th anniversary special and is set to air this week weekend.

He said: '''Thomas the Tank Engine' has been a comforting, familiar face to so many families over the last 75 years - entertaining, educating and inspiring children on important issues through exciting stories and characters.

''I certainly have fond memories of growing up with 'Thomas & Friends' and being transported to new places through his adventures.

''I am very proud to have been asked to take part in this special episode. I wish 'Thomas & Friends' a very happy anniversary.''

Harry filmed his introduction in January, and also made a donation to charity.

The 22-minute episode features some unique characters including Queen Elizabeth II, and the Prince of Wales as a child and also sees Rosamund Pike voicing the titular Royal Engine, which is named the Duchess of Loughborough.

And the actress hailed her role as an ''absolute honour''.

She said: ''It is an absolute honour to have the chance to appear in the show.

''I take it as a big responsibility to play Duchess, who is a lovely, warm, bubbly sort of effervescent engine that I am incredibly drawn to because she is very anxious to get things right.''

In the special, Sir Topham Hatt has been invited to London by the Queen to receive an award for distinguished service to the railway, and her son Prince Charles has asked that Thomas be the engine to bring him to the Mainland.

As this is the train's first time visiting London, he gets lost and finds himself in all sorts of predicaments, but it doesn't stop him from reaching his destination.

Chuck Scothon, SVP and GM of Infant and Preschool, Mattel, commented: ''Since the beginning, Thomas & Friends has celebrated friendship and teamwork through storytelling which has cultivated fan love across generations.

''In this milestone 75th year, we are releasing more storytelling content than ever before to engage the next generation of fans.

''While families are spending more time at home, we are able to offer new content to enjoy together across videos, books, apps and through music and podcasts and are thrilled Harry, The Duke of Sussex is introducing this special.''

'Thomas & Friends: The Royal Engine' will be screened on 'Channel 5 Milkshake!' at 9.05am on Saturday (02.05.20).