Gifted Brooklyn MC Mos Def [ tickets ] may be testing the acting waters on HBO, but Monday night (10/25) at the House of Blues in West Hollywood, CA, the rapper showed that his true calling was indeed standing with a mic in his hand, big beats booming behind him.

During this, the first of two performances of the night, the tough rapper marked the release of his second album, "The New Danger," opening the show with the disc's lead track, "The Boogie Man Song." The song's sparse, eerie beat set a dark tone--the perfect prelude to Halloween. Meanwhile, Mos Def, dressed in his trademark puffy black jacket, obscured his face with an outlaw-style handkerchief, sunglasses and a cap that settled just above his eyes. On "Ghetto Rock," also off his latest disc, Mos Def's DJ put together a fine, catchy beat as the rapper threw down his jacket and slung a white towel over his left shoulder.

After some quick introductions of his group--or at least the group of guys that took the stage with him, and hardly moved the entire show--Def welcomed longtime collaborator Talib Kweli onstage to roaring applause. In the late ‘90s, as Black Star, the two became hip-hop heavies with party-ready beats and intensely intelligent lyrics. Tonight, they worked the crowd with the skill and precision of their Brooklyn forefathers, Big Daddy Kane and KRS-One.

With Kweli at his side, Mos Def kicked into "Hip Hop," off his 1999 solo debut, "Black on Both Sides," immediately stirring the crowd into the archetypical hip hop posture: raised arms and bobbing heads filled the sweaty room. A visceral sight, to be sure. Next came "Definition," off the duo's 1998 album, and the loyal fans--many of whom had clearly been pleased with the Black Star reunion--sang along whenever Def or Kweli turned the mics in the audience's direction.

For a few songs, it seemed like 1998 all over again for the duo. Like their rhymes, Def and Kweli crisscrossed the stage, each one holding his mic close, pounding the crowd with an incessant flow. They offered the classic "Respiration" before dropping "I Try," off Kweli's latest, "The Beautiful Struggle."

Moments later, with the first notes of "Ms. Fat Booty" pouring out of the house PA, the fans were back in Mos Def's back pocket, singing along to the track's R&B-tinged refrain, "I know I can't afford to stop for a moment/That it's too soon/To Forget." Towards the song's end, the DJ gave way to a roomful of clapping and Def's acapella accompaniment.

In the end, though he played for just over an hour, Mos Def gave his fans all they could have asked for: a reunion with his legendary partner, a sampling of his latest dish, and some of his greatest hits, including "Umi Says." As the early crowd left and the next show's crowd waited to gain entry, Def and Kweli slid backstage to enjoy a break before doing it all again.