Britain's Prince William and his wife Kate head to India on Sunday for a tour that will see them mix with glamorous Bollywood stars and children from the Mumbai slums.

On their first official visit to the subcontinent, the royal couple will go to the Taj Mahal, scene of one of the most famous pictures of William's late mother Diana.

The Duke and Duchess of Cambridge will also visit Bhutan to go trekking through the remote Himalayan state and meet with King Jigme Khesar Namgyel Wangchuck and Queen Jetsun Pema.

"Our visit will reflect the best of the modern, forward-looking relationship between India and Britain," said William, 33, who is second in line to the throne behind his father Prince Charles.

The visit to the most populous country in the Commonwealth comes shortly before Queen Elizabeth II's 90th birthday on April 21.

The trip to the world's biggest democracy will further project them on the international stage as the future of the British monarchy.

Since December, William has made solo visits to key world powers such as the US, Japan and China as he plays an increasing role in representing Britain abroad.

Cricket, glitz and tigers  

"The duke and duchess are very much looking forward to their tours of India and Bhutan," said a spokesman for their Kensington Palace official residence.

"Their visit to India will be an introduction to a country that they plan to build an enduring relationship with.

"They will pay tribute to India's proud history, but also are keen to understand the hopes and aspirations of young Indian people and the major role they will play in shaping the 21st century."

Their children, two-year-old Prince George and Princess Charlotte, one next month, will be staying at home.

William and Kate will arrive in Mumbai on Sunday, where they will watch a youth cricket match and play with children from the city's slums.

They will then mix with Bollywood film stars and business chiefs from India's financial capital at a glittering red-carpet dinner.

They head to New Delhi late on Monday, where they will pay tribute to independence figurehead Mahatma Gandhi, meet leading politicians and attend a birthday party for Queen Elizabeth.

William is passionate about wildlife conservation and the couple will visit the Kaziranga National Park in eastern Assam on Tuesday and Wednesday.

The stay will see them find out how rural people live alongside elephants, water buffalo, tigers and rhinoceroses.

Memories of Diana  

William and Kate will then head across the border into Bhutan for two days.

They will meet the king and queen there after a colourful welcome ceremony and take a six-hour trek to Paro Taktsang, the spectacular Tiger's Nest monastery perched on a cliff edge.

They then return to India to visit the Taj Mahal in Agra on April 16 before departing.

Diana, princess of Wales, symbolically posed alone at the tragic monument to love in 1992, shortly before the collapse of her marriage to Charles was announced.

"The Duke of Cambridge is of course aware of the huge esteem his mother, the late princess of Wales is held in in India and he appreciates the iconic status of the images that exist of the princess at the Taj," Kensington Palace said.

"He feels incredibly lucky to visit a place where his mother's memory is kept alive..."

The Daily Telegraph newspaper said Kate would be taking 12 to 15 outfits for the trip, with some Indian designs likely to feature.