Flavor Flav was arrested early this morning in Vegas after  allegedly threatening a teenager in his house with a deadly weapon, TMZ has  learned.

Law enforcement sources tell us, the teenager  is the son of Flav's fiancee -- and the rapper had allegedly gotten into a  heated verbal argument with both the teenager and his mom before it turned  violent.

According to police, Flav -- real name William Drayton  Jr. -- is accused of getting physical with his fiancee and then  threatening her son with a knife. During the altercation, the fiancee called  911.

Flav was arrested around 3am and booked on two charges -- felony  assault with a deadly weapon and misdemeanor domestic violence  (battery).

He's currently being held on $23,000 bail.

Read more: http://www.tmz.com#ixzz29a8tQjBh