How sweet! Though Princess Charlotte became a big sister just a few days ago, the three-year-old has already proved to be the best older sibling to new royal baby Prince Louis. According to a new report, "Charlotte is really enjoying having a younger brother to play with. She’s taking her big sister duties very seriously. She won’t leave baby Louis’ side."

A palace insider told Us Weekly that Charlotte has learned from the best — her "protective" big brother, Prince George, 4. "Charlotte is just like him. They have a great bond, and a similar connection is growing between Charlotte and Louis," the source shared.

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And it's not just Charlotte who is experiencing royal baby bliss — the tot's dad and mom, Prince William, 35, and Kate Middleton, 36, are also reportedly thrilled about being new parents-of-three. "They are soaking up every minute they can. Their dream was always to have three kids," the insider said.

Prince Louis was born on April 23, just a few days before big sister Charlotte turned three years old on May 2. According to the royal insider, William and Kate pulled out all the stops when it came to celebrating their only daughter's birthday. "They like to make a fuss on the kids’ birthdays. There is always cake, her favorite dinner, and a lot of presents," an insider explained.

Another palace insider recently told Australia's Woman's Day that Charlotte is one of "the happiest royal tots in British history" and her idyllic upbringing is all thanks to her mom and dad. "They've got everything any child could ever want and — unusually for the Windsors — they've got two parents who completely and utterly dote on them," the source said.

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