Robert Pattinson was ready to rock in Los Angeles Sunday night.

The Twilight star, 26, attended The Black Keys' show at the Sayers Club with a group of pals, dressed down in a backwards hat, button-down shirt and jeans, an eyewitness tells Us Weekly.

"Rob was definitely enjoying the music, getting more into it as the set went on," the witness says. "He cheered and clapped at the end of each song."

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Pattinson indulged in an electronic cigarette, and sipped on beer and mixed drinks throughout the evening.

He "was clearly enjoying the music and in a good mood," the witness adds. "In between songs he would make comments or joke around with his friends."

All in all, the seemingly carefree Cosompolis actor "seemed really happy and comfortable all night." After the show ended, Pattinson hung around for one more beer with his friends, and posed for a photo with 98.7 FM DJ Kennedy.

Pattinson has good reason to be smiling these days: as Us reported last week, he and his girlfriend Kristen Stewart "are living together and have reconciled" two months after the actress' fling with her married Snow White and the Huntsman director, Rupert Sanders.

Although Stewart managed to win her man back, she still has one major obstacle to overcome: convincing Pattinson's friends, who advised him to end things with her once and for all, that she can be trusted.

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"They don't want to see him get hurt again," an insider explained. Still, as another source added, "Rob has hope in their romance."

On Monday, Deadline reported that the couple of three years are both scheduled to appear at the worldwide press junket for Breaking Dawn -- Part 2 in Los Angeles; no word yet on whether Pattinson and Stewart will appear together at subsequent promotional events for Twilight's final installment.

This article originally appeared on Robert Pattinson "Really Happy and Comfortable" at Black Keys' L.A. Show