One hot mama!

Pippa Middleton is looking crazy good just 11 weeks after welcoming her son, Arthur. The new mom showed off her chiseled abs on a beach vacation in St. Barts on Wednesday.

SEXIEST CELEBRITY BIKINI BODIES

The 35-year-old sister of Kate Middleton rocked a sexy white bikini while taking a dip with her husband, James Matthews. Pippa gave birth to her son in October, shortly after attending the royal wedding of Princess Eugenie and Jack Brooksbank.

She mostly kept her pregnancy low-key and under wraps, only confirming the pregnancy in a column for Waitrose Kitchen magazine in June. At the time, she focused on her approach to exercise during pregnancy.

Pippa Middleton (Splash)

PIPPA MIDDLETON PROUDLY SHOWS OFF BABY BUMP AT PRINCESS EUGENIE'S ROYAL WEDDING

“I’m fanatical about sport and have looked at loads of books and websites on exercise during pregnancy but have been disappointed by the limited technical information on what you can and can’t do,” she wrote at the time. “I decided to use my own initiative and adapted my current exercise routine, adjusting the weight and intensity to what felt right for me.”

Looks like that plan panned out for the fit new mom!

PIPPA MIDDLETON SAYS 'REALITY IS FINALLY KICKING IN'