LONDON -- Prince Charles said Tuesday it is a "great joy" to be a grandfather once again with the birth of a third child for the Duke and Duchess of Cambridge.

The duchess gave birth to the 8-pound, 7-ounce (3.8 kilogram) boy Monday morning at St. Mary's Hospital in London. The new prince is a younger brother to 4-year-old Prince George and Princess Charlotte, who turns 3 next week.

Charles said in a statement that "it is a great joy to have another grandchild, the only trouble is I don't know how I am going to keep up with them."

As the new family of five spent time at home at Kensington Palace, the birth was marked Tuesday by bell ringing at Westminster Abbey and gun salutes in Hyde Park and at the Tower of London.

The new baby is a sixth great-grandchild for Queen Elizabeth II and is fifth in line to the throne after Charles, father Prince William and his two older siblings.

William and Kate have not yet disclosed the name of the infant prince. Bookmakers say Arthur is the favourite in betting, followed by James and Albert.