Prince George's Mischievous Cousin Savannah Turns 11 — 4 Moments That Landed Them in Royal Trouble!

Prince George may be the future monarch, but his older cousin Savannah Phillips is known for keeping him humble...and giggling at the worst times!

Queen Elizabeth's eldest great-grandchild, the daughter of Prince William's cousin Peter Phillips and his ex-wife Autumn, celebrates her 11th birthday on Wednesday. Savannah has charmed royal fans during equestrian events with her family (after all, both her grandmother Princess Anne and aunt Zara Tindall have competed in the Olympics) and is a sweet big sister to 9-year-old Isla, but she has a cheeky streak that often involves 8-year-old Prince George!

The duo first caught the attention of royal watchers at the 2018 Trooping the Colour festivities. As the royal family gathered on the Buckingham Palace balcony to watch the flypast, Prince George caught a case of the giggles — prompting Savannah to cover his mouth and flash a deadpan look, seemingly knowing the cameras were watching. She was also seen placing a finger over her mouth to shush the future king.

Also watching was Prince William, who looked less than amused by the little ones' antics!

Just one day later, Savannah and George reunited to cheer on Prince William at his charity polo match in Gloucester, England. During the playdate, which included running around the field and playing with a Slinky, Savannah playfully pushed Prince George down a hill when he attempted to sit next to her.

Though George wasn't injured and regained his balance, Savannah wasn't unscathed as she was scolded by mom Autumn immediately after.

Savannah's joking didn't end there — she was also spotted ruffling George's hair when he wasn't looking.

The cousins were back to goofing off at Princess Eugenie's wedding in October 2018, where they served as members of the bridal party.

As they were waiting to walk down the aisle ahead of the bride, Savannah was spotted making George laugh by imitating the trumpet players providing entrance fanfare for the ceremony. Perhaps the son of Kate Middleton and Prince William realized the cameras on him — he was photographed covering his mouth with his eyes wide as if he'd been caught!

When Princess Eugenie and Jack Brooksbank shared their official wedding portraits, Savannah can be seen placing one foot on the train of the bride's gown as she smiled for the photo.

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Prince William recently opened up about Christmas with the royals, including that one of his favorite parts was bringing the family together.

"When I see my children meet up with my cousin's children, and they all have a wonderful time playing together, it's very special," he said. "I look forward to that a lot."