The Duchess of Cambridge Kate Middleton revealed a big baby bump at the Buckingham Palace garden party in London, where Queen Elizabeth II hosted about 8,000 members of the public.

The 31-year-old duchess who will welcome her first child with Prince William in July, showed off her baby bump in a round-neck canary yellow silk coat by Emilia Wickstead accesorized with a cream hat by Jane Corbett, according to the Daily Mail. She also wore nude heels and pearl drop earings at the event on May 22.

This is Middleton's second annual garden party and she attended with Prince Charles and Camilla, Duchess of Cornwall.

People attending included Olympians, Paralympians and officials from the Olympic Games in London last year, according to media reports.

Middleton will be giving birth to a boy, according to the Sunday People. While Prince William and Middleton have not made any official announcement about the gender of the baby, Prince Harry has reportedly been telling close friends that the couple are expecting a boy.

"Harry has been telling everyone Wills and Kate are having a boy and how thrilled he is at the prospect of hacing a little nephew," the Sunday People reports, citing a source close to the Prince.

Prince William has been outspoken about his excitement to welcome the couple's first baby. At a recent visit at the Help of Heroes recovery center, he reportedly said that he was "very much" looking forward to becoming a dad while he also joked about the sleepless nights.

"All the mothers have been looking at me, 'just you wait, just you wait. Long sleepless nights,'" he said, according to the Daily Mail.