Jennifer Aniston Sings Happy Birthday -- VIDEO

Check out this clip of Jennifer Aniston singing “Happy Birthday” yesterday on 30 Rock.

According to E!, last night’s episode was watched by a season-low 7.5 million. The show’s previous low (8.1 million) came a week ago when Oprah made a cameo.

Her boyfriend John Mayer just expressed how happy he is that they’re together again: “It’s really nice to have somebody in life have your back. That girl knows me … so whether I go to bed alone or not, to have somebody who knows you in this world, that’s a really nice thing.”

WHAT DO YOU THINK of Jennifer Aniston’s singing — HOT or NOT?