Jay-Z throws big b-day bash for wife Beyonce

Beyonce Knowles' hubby Jay-Z threw an intimate party to celebrate his wife's 29th birthday.

He took over nightlife impresario Scott Sartiano's and Richie Akiva's about-to-open Chelsea restaurant, The Darby, and invited friends including Alicia Keys, Serena Williams, Kanye West and Sean "Diddy" Combs to toast Beyonce . . . while DJ Cassidy took over the decks.

"Jay brought a six-layer cake out for B, they were really affectionate. Cassidy played Stevie Wonder's 'Happy Birthday,'" the New York Post quoted a source as saying.

"The party went on until 6 am. Both Jay and B's moms were there, but there was no sign of her father or her sister. Diddy was the last to leave. Jay filled the room with orchids," the source added.