According to Us Weekly, the star of hit TV show, Criminal Minds, welcomed a baby boy into the life she shares with husband, Nathan Anderson and their six-year-old son, Mekhai Allan.
It is understood that the 37-year-old actress, who announced her pregnancy in March, gave birth to baby Phoenix Sky Anderson earlier today.
A.J made no secret of her delight at the prospect of becoming a mum again, having posted a truly touching message on Instagram informing fans and followers of the impending arrival.
Melting hearts all over the world, a delighted A.J wrote: "Miracles do happen and don't believe anyone who tells you otherwise."
The star finished the post by hashtagging the words 'Blessed' and 'Bump' beside a photo of her burgeoning bump.
Equally as happy, Nathan took to his own social media channels, writing: "Since @ajcook announced we are expecting a new addition to the clan, I guess it's my responsibility to inform everyone it's a boy!"
According to the star's representative, baby Phoenix weighed in at a healthy 7 lbs 6 oz and measured 20.5 inches on delivery.
Congratulations guys!
