Beyonce makes surprise appearance at Jay-Z Barclays Center concert last night (VIDEO)

Beyonce made a surprise appearance last night at Jay-Z's last show in his concert series at the Barclays Center in Brooklyn.

Donning a black Nets cap, dark sunglasses, a loose-fitting shirt, shorts and thigh-high boots, the singer opened her set with "Diva," off her 2008 album "I am... Sasha Fierce."

She then went into"Crazy in Love," which ran smoothly until her husband missed his cue on his rap part.

"Oh sh*t, I should probably rap here," he later explained. MTV News said Jay told the audience he was so caught in the moment of watching Beyonce on the T.V. monitors that he forgot to go out.

Not everyone, however, was pleased with Queen Bey's performance.

Music blog site The Lava Lizard, ran by music critic Trent, called her performance "odd," saying she seemed out of breath.

"From the missed cues to the out of breath vocals and sluggish dancing, Beyonce was definitely not in prime form this evening. In fact, add those factors to her fashion choices and it's easy to assume that she just might be pregnant again. Either way, her appearance at Barclays was fun to watch a treat for her adoring fans," Trent said.

His commenters seemed to be in accord.

"This is prob one of her weakest performances.. i mean she still completely (did better than) most peoples best but yeah this was surprisingly tame.. she either decided to do it last min and threw it together or shes preggo," user Brendan said.

Girrl took it easy on the new mom, saying "she's probably getting used to performing again."

Liberiangirl responded with "Or she didn't use "pre-recorded" vocals this time and actually sung "live."

Beyonce made a much-publicized, post-pregnancy performance at the Revel casino in May, where she received rave reviews from audiences and critics alike.

Even her husband Jay made a somewhat stunning statement on Twitter, calling Beyonce the "best performer in the world. Period."

Jay-Z inaugural eight shows at Barclays kicks off New York City's newest arena. The Barclays Center is located just two miles away from Jay's birthplace, the Marcy Projects.