Jay-Z celebrated the grand opening of the Barclays Center's 40/40 club Thursday night (Sept. 27) in Brooklyn, N.Y. Hov's closest friends like Rihanna, Questlove (of the Roots), J. Cole and other celebrities were in attendance at the club's first party inside the Brooklyn Nets' new home.

The Roc Nation honcho, who is a minority owner of the Brooklyn Nets, will christen the $1 billion arena with an 8-concert residency starting on Sept. 28 through Oct. 6.

At the party, Jay-Z was dressed to the nines in a black tuxedo, while Rihanna came through wearing a pajama-style outfit which was half-buttoned to reveal her navel. Roc Nation artist J. Cole, who was photographed with Ri-Ri, came casual in a white dress shirt, black vest, blue jeans and black Air Jordans. Drummer Questo was looking very dapper in his black suit with a red gingham shirt and black tie.

Anticipation surrounding the Barclays Center and Jay-Z's string of eight concerts has reached a fever pitch. But the rap mogul seemed calm about the whole thing.

"I walked around here earlier and I just seen everybody busy and at work trying to finish up, and it was a great feeling," he said. "A guy stopped me in the hallway and said, 'Man, this is a great thing for New York City.' And that's what the whole thing was about."

It's the Roc!

Watch Jay-Z Celebrate the Opening of 40/40 Club at Barclays Center