Look: Prince George appears in new photo on his 13th birthday

July 22 (UPI) -- British royal Prince George is celebrating his 13th birthday.

George, the son and eldest child of Prince William and Kate Middleton, appeared in a new photo to mark the occasion Wednesday.

The image shows George smiling for the camera as he poses in a stairwell. The prince wears a black suit jacket and pants with a white collared shirt.

"Happy 13th birthday, George!" the caption reads.

Kensington Palace announced in June that George will attend Eton College starting in September. William, his brother Prince Harry and their father King Charles also attended the elite private school for students ages 13 to 18.

William and Middleton, formally known as Catherine, princess of Wales, married in April 2011 and have two other children: Princess Charlotte, 11, and Prince Louis, 8. George is second in line for the British throne.