King Charles had paid a tribute to his "dear cousin" King Harald after the monarch's death
Prince William and Princess Anne were among thousands of people who attended the funeral of Norway's King Harald on Wednesday.
The Prince of Wales and the Princess Royal were seen arriving at RAF Northolt this morning.
Prince William and Princess Anne traveled from RAF Northolt to Oslo, Norway, to attend the state funeral of King Harald V.
Norway's King Harald was laid to rest in a series of ceremonies marking the culmination of 13 days of national mourning following his death at the age of 89.
Tens of thousands of people lined the capital's Karl Johan Avenue, police said, with crowds falling completely silent as the coffin passed.
The procession was followed by a church ceremony starting at 1300 local time (1100 GMT). It began with a nationwide minute of silence.
Japan's Crown Prince Akishino and Crown Princess Kiko; Spain's King Felipe, Queen Letizia and Queen Sofia; Sweden's royal family; and Denmark's King Frederik and Queen Mary.
Heads of state from around the world were invited.