Prince William stepped out for a favorite cause amid his family members’ recent health news.

The Prince of Wales, 41, returned to royal duty on Wednesday for the first time since news broke last month of his wife Kate Middleton’s abdominal surgery on Jan. 16 as well as his father King Charles‘ cancer diagnosis, revealed earlier this week.

After hosting an investiture ceremony at Windsor Castle in the morning, Prince William headed to London for the London’s Air Ambulance Charity Gala Dinner. As he arrived, William quickly answered a question about the public support in recent weeks: “We really appreciate everyone’s kind messages. Thank you.”

The event, held at a central London hotel, had the aim of raising funds for the London Air Ambulance, which Prince William has supported for about four years. The organization is hoping to bring in $19 million by the fall.

William began the evening by meeting crew members, former patients and supporters of the charity.

Tom Cruise was a fellow guest at the event, and the pair posed together for photos in their tuxedos and black bow ties.

Sharing a photo of their reunion on social media, Prince William’s team wrote, “Fancy seeing you here, @TomCruise!” complete with a helicopter emoji.

Prince William previously met the actor on several occasions, most recently at the London premiere of Top Gun: Maverick in May 2022 alongside Princess Kate. Cruise, 61, also attended the funeral of William’s mother, Princess Diana, in 1997.

Prince William is expected to use the occasion to speak for the first time about the cancer diagnosis of the King, 75. He is also expected to address Princess Kate’s surgery and her recuperation in a speech during the event. She is staying at the couple’s home Adelaide Cottage in Windsor and is unlikely to return to public duties until after Easter. 

The rapid response of the London Air Ambulance service can bring the hospital emergency department to the scene of an incident anywhere in London. It has delivered life-saving treatment to more than 45,000 people since its foundation in 1989.

As a former air ambulance pilot in East Anglia, Prince William is passionate about supporting the emergency services in all their forms. He has been a patron of the charity for four years and took to the air in one of the organization’s helicopters to mark the 30th anniversary of the service. 

Prince William’s appearance came a day after King Charles met with his younger son, Prince Harry, who had jetted in solo from California overnight Monday. King Charles and Queen Camilla, 76, left London for their country home, Sandringham House, in Norfolk soon after he met with Harry, which lasted less than an hour. 

The Prince of Wales did not meet with his brother, 39, before Prince Harry was spotted at the London airport on Wednesday.

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Prince William isn’t expected to make any more public appearances for more than a week as he continues to focus on his wife’s health and helping care for the couple’s three children: Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5. Next week is the children’s half-term vacation from school.

A royal source tells PEOPLE exclusively in this week’s issue that the Prince of Wales is in regular contact with his father amid the news of the King’s cancer diagnosis. As King Charles steps back from public engagements and Princess Kate continues her months-long recuperation, it’s up to Prince William (along with Queen Camilla) to be the face of the monarchy.

“It is hard with Kate being ill as well, but he will step up,” says a source close to the royal household.

Although Prince William may undertake some duties on behalf of his father, there are currently no plans to appoint Counsellors of State to act on King Charles’ behalf. In times of need, the British sovereign can call on these members of the royal family to help manage the monarchy by acting on their behalf through the Letters Patent in the event of temporary incapacity or absence from the U.K.

“He wouldn’t want to put that pressure on William,” says the source. “He has always wanted to save his children from having that pressure too early and that will remain. Particularly as William has other priorities [with Kate].”