Kate Middleton has publicly congratulated her younger sister after she gave birth yesterday.

Pippa and her husband James Matthews welcomed their first child, a son, on Monday afternoon in the Lindo Wing of St Mary's Hospital in London - the same place Kate and Prince William had each of their three children. Kensington Palace released a short statement in reaction to the news, saying; "The Duke and Duchess of Cambridge are thrilled for Pippa and James." Pippa today received her first visitor, her brother James Middleton. He was snapped by photographers as he made his way to meet his new nephew. Her parents Carole and Michael could also stop by but it's not expected that Kate will visit her sister in hospital. Kate showing up at the Lindo Wing would cause an intense media flurry - probably not what new mum Pippa wants when she's recovering after giving birth. Instead it's speculated that Kate will be one of Pippa's first visitors when she takes her new little boy home from the hospital, just as Pippa and the rest of the Middletons have visited Kate at home after each of her three births. Pippa was last seen in public when she attended Princess Eugenie's wedding in Windsor on Friday - just three days before she gave birth.