The pair were seen at the Hollywood Roosevelt hotel and couldn't even be parted when visiting the restroom.
A source told the New York Post newspaper: "Britney and Brandon were getting along really well. They even went to the bathroom together." The two 25-year-olds were first seen on a dinner date together in Los Angeles last Thursday (30.11.06).
Oil heir Brandon was close friends with Britney's new best friend Paris Hilton.
However, Paris and Brandon are no longer on speaking terms after their friendship and rumoured romance came to a bitter end earlier this year.
Brandon recently branded Paris a racist, saying she was forever referring to black people as "n*****s".
He said: "She is a racist, plus an idiot. I don't want anything to do with her. I don't need anything from her. She is no longer my friend. She is just not a nice person." Brandon has also attacked Lindsay Lohan labelling her 'firecrotch' and adding that she "smelled of diarrhoea".
Paris joined Britney for her 25th birthday celebrations on Saturday night (02.12.06).