kimora-lee-simmons-birthday-newborn

Happy 40th to Kimora Lee Simmons!

To celebrate her milestone birthday, the mom-of-four took to Instagram Monday with a sweet snapshot of her newborn son Wolfe.

“Today’s my birthday. I’m such a lucky girl to wake up to this gorgeous little man and my beautiful husband, kids and family. This is how it’s supposed to be… I woke up like this….!! #ItsMyBirthday! #SuperBlessed #WolfeLee #11poundBaby #MotherOfFour,” she captioned the photo kissing her baby boy.

The reality star — also mom to daughters Ming, 15, and Aoki, 12, with Russell Simmons, as well as 5½-year-old son Kenzo with Djimon Hounsou — welcomed Wolfe with husband Tim Leissner.

“Wolfe was a big boy! Handsome just like his father,” Simmons recently said. “[Wolfe was] 11 lbs. — a lot of work. But a labor of love! We’re all so happy he’s here.”

She added: “My fourth delivery was definitely the most challenging — all natural and with no drugs! It really shows that moms-to-be have the power to deliver any way they choose. Choice is what’s most important for women — across the board.”

Today’s my birthday. I’m such a lucky girl to wake up to this gorgeous little man and my beautiful husband, kids and family. This is how it’s supposed to be… I woke up like this….!! #ItsMyBirthday! #SuperBlessed #WolfeLee #11poundBaby #MotherOfFour

A photo posted by Kimora Lee Simmons (@officialkimora) on May 4, 2015 at 8:31pm PDT