Twitter meltdown: Princess Charlotte steals the show at brother's birth

The world watched as Kate Middleton went into labour with her third child, but it was Princess Charlotte who stole the show.

The 3-year-old seemed at ease in front of the press as she entered the Lindo Wing at St Mary's Hospital to meet her new little brother, reports the Daily Mail.

Her little royal wave sent Twitter users into meltdown as they commented on how cute the "professional" young girl was.

Prince William went to collect his two eldest children to meet the newborn before swiftly returning to the hospital with them in each hand.

Prince George and Princess Charlotte treated the public to an adorable apperance. Photo / Getty Images

Princess Charlotte greeted those waiting outside and even glanced back and gave a cheeky royal wave as she walked through the hospital doors.

Despite the princess' young years, one user commented that she had "all the makings of a great queen".

Adoring fans said that the young princess was "legit the cutest thing ever" and that she could be the next Diana.

Another added that she was the most adorable little girl she had ever seen, especially because of her wave.

One Twitter user said: "Princess Charlotte completely stole the show she is the cutest little girl and her little wave really did melt my heart."

Meanwhile another user said that Charlotte's royal wave was her favourite thing on the internet this week "and it's only Monday".

Raise your hand if Princess Charlotte’s wave killed you. 🙋🏼‍♀️

— Sarah (@ClassyFabSarah) April 23, 2018

"We all know who the REAL star of this family is!" 🌟 #RoyalBaby #PrincessCharlotte pic.twitter.com/bBjILv165U

— InStyle (@InStyle) April 23, 2018

Princess Charlotte waving is EVERYTHING #royalbaby #scenestealer

— Aaron Keeling (@aaronjkeeling) April 23, 2018

i’m gonna let the #RoyalBaby trend finish, but Princess Charlotte is the cutest Royal of all time 😭👑 pic.twitter.com/CCgxgNFWBD

— AB (@ashtonbry) April 23, 2018