The Prince of Wales will begin his four-day visit to Singapore on Sunday in support of the third Earthshot Prize Awards ceremony, taking place on Tuesday.
Prince William will be flying solo throughout the trip as his wife, the Princess of Wales, has remained in the UK.
And there's a very important reason behind Kate's absence.
William and Kate's eldest son Prince George's exams coincide with the Earthshot Awards, and it's understood that the Princess has stayed in the UK to support the young Prince.
George, ten, who is in Year 6 at Lambrook school in Berkshire, is likely to be sitting entrance exams for his future private school.
The ISEB Common Pre-tests are usually taken in Year 6 or 7 and consist of four sections - mathematics, English (reading, comprehension and grammar), verbal reasoning and non-verbal reasoning.
George isn't likely to move schools until the age of 13, but entrance exams are usually sat three years in advance.
Among the future school options for George are Eton College in Windsor, attended by his father, or his mother's alma mater, Marlborough College in Wiltshire.
Our co-hosts on HELLO!'s A Right Royal Podcast recently took a deep dive into the royal family's education, including George, Charlotte and Louis' academic futures. Listen below…
During an outing with William in Cardiff last month, Kate revealed how she's been helping her eldest child to prepare for his upcoming exams.
"I've been helping George prepare for his exams coming up, so I know how hard maths can be," Kate told sixth formers who were preparing for their maths A-levels.
"George is just at the beginning of being tested. He says: 'Mummy, I keep getting tested all the time.' But when it gets to A-levels you feel like you're on it."
See the moment in the clip below...
George, Charlotte and Louis returned to their classrooms at Lambrook earlier this week after enjoying the October half-term break with their parents.
William was joined by George for Wales's quarter-final match against Argentina in Marseille, France at the Rugby World Cup, at the start of the school holidays. Sadly, Wales were knocked out of the tournament.