Kate Middleton just said the sweetest thing about Meghan and Harry's baby boy.

As you may be aware, Meghan Markle and Prince Harry welcomed their first child yesterday and the news was met with great excitement. Of course, their family and friends are delighted and Harry's brother, William, and William's wife Kate Middleton expressed their joy during an official engagement today. The couple launched the Kings Cup Regatta in Cutty Sark, London and of course, royal reporters were only too eager to ask about their new nephew. Emily Andrews, the royal correspondent for The Sun, was in attendance and shared some videos from the event where Kate and William look overjoyed and keen to congratulate the Duke and Duchess of Sussex. Harry's older brother was keen to welcome him to the "sleep deprivation club", cracking one of the dad jokes he's become known for.

VIDEO: William & Kate say they look forward to meeting #babysussex. Wills: “We’re absolutely thrilled & look forward to seeing them in the next few days... I’m v pleased to welcome my brother to the sleep deprivation society that is parenting!” pic.twitter.com/W6ldWWsUgn

— Emily Andrews (@byEmilyAndrews) May 7, 2019

William also said that they would meet the latest member of the royal family in the coming days.

"We’re absolutely thrilled & look forward to seeing them in the next few days... I’m pleased to welcome my brother to the sleep deprivation society that is parenting!".

Kate also chimed in and said that it was a very "exciting" time but also recognised that it can be a "daunting" experience for new parents, particularly if it's their first time as mum and/or dad. The mum of three also went to acknowledge that it "spring is in the air" and it's a special time of year to have a baby with two of her children, Charlotte and Louis, having recently celebrated their birthdays. CUTE. It's a busy time for the Duke and Duchess of Cambridge who travel to North Wales tomorrow for a number of royal engagements. This is sure to be a special trip for the couple as they lived there for a time when they were first married.