The former N-Dubz star Dappy has been arrested after allegedly threatening a woman and carrying a knife in public.
Armed police were called to an altercation between a man and woman in a residential street in Hatfield, Hertfordshire on Wednesday afternoon.
Costadinos Contostavlos, who performed as Dappy and appeared in Celebrity Big Brother, was arrested in College Lane.
Police said a 29-year-old was being held on suspicion of assault and possession of a knife in public.
Hertfordshire Constabulary said: "The man threatened the woman before leaving the scene. It is believed he had a knife. No one was seriously injured."