Prince William turns 35: How the royal is reshaping his role

— -- Prince William is expected to celebrate his 35th birthday privately today with family members including his wife, Princess Kate, and their children, Prince George and Princess Charlotte.

The heir to the British throne is taking on an increasingly high-profile role in his royal duties and drawing comparisons to his late mother, Princess Diana. William spent the day before his birthday at the 2017 Royal Ascot with his grandmother, Queen Elizabeth II, and other members of the royal family.

William has been stepping up his royal duties and supporting his grandmother as a changing of the guard takes place. Buckingham Palace announced earlier this year that William's grandfather, Prince Philip, 96, who was hospitalized today in London, will step down from public life this fall.

William's and Kate's first priority has been to shield their children, George and Charlotte, from the media so they can enjoy as normal a childhood as possible.

Recognizing the public's interest in them, however, William and Kate have also slowly been introducing George and Charlotte to public life, most recently taking them to the queen's official birthday celebration, Trooping the Colour, last weekend.

Prince George, who will turn 4 in July, accompanied his parents to the Royal International Air Tattoo last July, and he and Charlotte, 2, traveled with their parents on an eight-day tour of Canada last September.

William and Kate will travel to Germany and Poland in July to promote the U.K.'s interests in the region as they increase their diplomatic profile on behalf of Queen Elizabeth. In March, the couple met with France's president at the Elysee Palace and attended a black-tie dinner at the British Embassy on a two-day charm offensive in France ahead of England’s planned exit from the European Union.

Later this summer, William will leave his job as an air ambulance pilot with the East Anglia Air Ambulance as he continues to take on more royal duties to support the queen, who is still very active at 91 but relying on her children and grandchildren for longer royal trips. He and Kate will also "increasingly base" their family in London, according to a statement issued by Kensington Palace in January.

The move from the family's primary residence, Anmer Hall in Norfolk, to their apartment in Kensington Palace will also come as Prince George will start primary school at Thomas's School in Battersea in the fall.

William and Kate have also taken the helm of several patronages recently passed onto them by Queen Elizabeth, 91. Kate became Wimbledon Tennis Club’s official patron, while William has taken over from his grandmother as the Welsh Rugby Union's patron.

The couple has also become more involved in the high-profile Heads Together mental health campaign and the Royal Foundation, both of which they formed with Prince Harry. The royal trio have become high-profile advocates on a number of key issues close to their heart and have said they feel it is important to use their position to make a difference in the lives of the less fortunate.

William -- who with Harry has taken up charitable initiatives like homelessness and HIV awareness pioneered by Princess Diana -- used his platform as an advocate for mental health awareness to open up publicly about the death of his mom and its impact on him and his family.

"I am in a better place about it than I have been for a long time, where I can talk about her more openly, talk about her more honestly, and I can remember her better, and publicly talk about her better,” William told GQ magazine in an interview published in May. "It has taken me almost 20 years to get to that stage. I still find it difficult now because at the time it was so raw."

He followed in Diana's footsteps in May by making a visit to the Royal Marsden Hospital, of which Diana was president and patron of the hospital until her death in 1997. William, who has since stepped into his mother's role, visited with young cancer patients at the hospital's Sutton location as he marked 10 years of his association with the hospital.

More recently, William accompanied Queen Elizabeth last week to meet with victims of the Grenfell Tower fire in London. At one point William embraced an emotional woman who was desperate to find her missing husband.

Earlier this month, William made another unannounced visit, this time to meet with survivors and first responders of the Manchester Arena terror attack that killed 22 people.