Proud dad Jay-Z, real name Shawn Carter, was at the hospital where Beyonce reportedly birthed Ivy by c-section -- and shortly after her arrival ... J & B's famous friends started sending out birth announcements on the Internet.
Rihanna tweeted, "Welcome to the world princess Carter! Love Aunty Rih"
Hip-hop mogul Russell Simmons also took to Twitter, saying ... "congrats to my good friends Beyonce and Jay-Z."
Diddy added :“Congrats to jay and B! God Bless
! And many more!”We here at Kelsnetwork congratulate Beyonce and Jay Z!
Beyonce famously announced her pregnancy on stage at the MTV Video Music Awards back in August.
-TMZ
