Duchess Kate turns 31: How is she celebrating?

Britain's Catherine, Duchess of Cambridge, wife of Prince WiIliam, leaves the King Edward VII hospital in central London, on Dec. 6, 2012. / LEON NEAL/AFP/Getty Images

Mom-to-be Kate, Duchess of Cambridge is not celebrating her 31st birthday Wednesday with a big blow out, according to a report.

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Kate, Duchess of Cambridge

Instead, Duchess Kate is celebrating her birthday "privately," according to a rep for St. James's Palace told Us Weekly.

"She just wants something low-key," a source told the magazine. "I suspect she will spend it at her parents' house."

According to People, Kate will be reunited with her husband William, who was serving on a Royal Air Force search and rescue crew over the holidays.

Last year the duchess chose to celebrate her birthday in a similar "low key" fashion, having a private dinner with friends and family.