UK's Prince George starts school, pregnant mum Kate too ill to go

Prince George holds his father Britain's Prince William's hand as he arrives on his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool

LONDON (Reuters) - Britain's Prince George, the great-grandson of Queen Elizabeth and third-in-line to the throne, started school on Thursday but without his pregnant mother Kate to support him because she is suffering from severe morning sickness.

George, 4, was taken by his father, Prince William, from their Kensington Palace home to Thomas's Battersea school in southwest London, which says its most important rule is to "Be Kind" and charges almost 18,000 pounds ($23,490) per pupil per year.

"We expect our pupils to make impressive progress as a result of their own hard work, the best efforts of their teachers, the judicious support of their parents and the encouragement of their peers," the school says on its website.

Prince George holds his father Britain's Prince William's hand as he arrives on his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool

A nervous-looking George, wearing a school uniform of dark shorts and a navy jumper with red trim, held his father's hand as the Head of Lower School, Helen Haslem, escorted the royal duo to his classroom.

His mother Kate missed the occasion due to acute morning sickness and has canceled other engagements this week after the palace announced on Monday that she was expecting her third child.

Like his parents, George and his younger sister Charlotte have already appeared on the front covers of magazines around the world and this summer they traveled on official royal tours of Poland and Germany where crowds cheered them.

Prince George holds his father Britain's Prince William's hand as he arrives on his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool

(Reporting by Michael Holden, editing by Estelle Shirbon)

Helen Haslem, head of the lower school and Britain's Prince William hold Prince George's hands as he arrives for his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool

Helen Haslem, head of the lower school and Britain's Prince William hold Prince George's hands as he arrives for his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool

Britain's Prince William accompanies his son Prince George on his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool

Helen Haslem, head of the lower school and Britain's Prince William hold Prince George's hands as he arrives for his first day of school at Thomas's school in Battersea, London, September 7, 2017. REUTERS/Richard Pohle/Pool