Princess Beatrice Just Upstaged Everyone At The Queen's Birthday Service

It's her party, and she'll get upstaged by her granddaughter if she wants to. 

A slew of 90th birthday celebrations already happened for Queen Elizabeth II back on the day she was born, April 21. But in accordance with royal excess, she gets yet another whole weekend full of official, additional celebrating , starting now.

To kick things off, the whole gang royal family was on hand for a thanksgiving service honoring her majesty at St. Paul's Cathedral in London Friday.

The birthday girl looked lovely in a matching yellow Angela Kelly dress, hat and coat. The Duchess of Cambridge -- you may remember her as Kate Middleton  -- arrived with Prince William and Prince Harry.  She also dressed up for the occasion in a Catherine Walker coat and Jane Taylor hat.

But the real winner of the entire day has got to be Princess Beatrice, who arrived at the service in a black and white Burberry coat that, no offense, makes Kate's sweet little look seem like child's play.

Her sister, Princess Eugenie, also looked great in a red dress with cut-outs. But Beatrice simply takes the birthday cake this time around, what with the bold pattern, coordination and stormtrooper comparison .

You go, Princess Beatrice!