Miley Cyrus Calls Herself A "Stoner" At 19th Birthday Party

Looks like Miley Cyrus better start censoring herself around some of her friends!

The Hannah Montana star celebrated her 19th birthday on Nov. 23 -- thrown by pal Kelly Osbourne -- at Beacher's Madhouse at the Hollywood Roosevelt Hotel, on Saturday night.

But when friends brought out a "Bob Miley" cake for the former Disney star, she took to the microphone to declare her love of the green stuff.

In a video obtained by The Daily, Miley can be heard saying:

"This is amazing. You know you're a stoner when your friends make you a 'Bob Miley' cake. You know you smoke way too much f––ing weed."

Osbourne then took control of the mic, telling the birthday girl: "I thought salvia was your problem, Miley."

Cyrus was caught smoking "salvia" last year out of a bong, which she quickly apologized for, calling it: "A bad decision, because of my fans and because of what I stand for."

While the Last Song star has yet to make a comment on the most recent incident, BFF Kelly has taken to Twitter to defend her friend, expressing:

"let me make something very clear after @MileyCyrus salvia incident we started calling her bob miley as a JOKE! ... the cake was also A JOKE! it makes me sick that @MileyCyrus so called 'friends' would sell her out and lead people 2 believe she is someone that she is not!"

Osbourne added: "u guys if @MileyCyrus is not recording/filming/touring she is works everyday how could she possible do all that if she was a stoner! #think."

Do you think Miley was joking? See the full video below ...