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"Milkshake" singer Kelis is a new mom!

The singer, 29, gave birth to baby boy named Knight on Tuesday.

Kelis' ex, rapper Nas, posted an online video celebrating the birth of his son.

"My son is born today, so shout-out to my son, Knight," the rapper said in a clip.

Us Weekly exclusively revealed Kelis' pregnancy last January. At the time, she was still married to Nas, 35, who is also dad to a 15-year-old from a prior relationship.

"It's all they are talking about," a source told Us at the time of Kelis and her ex. "She is carrying hip-hop royalty! They are so excited."

The couple called it quits in May after Kelis, then 7 months pregnant, filed for divorce citing verbal abuse and infidelity, according to Vibe, which first reported the break up.

The couple -- who met at a 2002 MTV Video Music Awards afterparty thrown by Diddy -- tied the knot in a small ceremony in Atlanta in January 2005.

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