The California based band who are sued the UK / Irish boy band One Direction for using their band’s name have been receiving death threats from upset fans.

The US band say that since announcing their lawsuit again One Direction they have received a large number of death threats and hate mail from adoring fans of the “X Factor” band.

Sean O’Leary, the 18-year-old lead singer with the Californian band told the Sun “There has been so much hate mail, like people threatening to cut our balls off.”

He said the death threats to his father and band manager have been the most disturbing.

O’Leary said “The one that stands out for me is a girl saying she wanted to kill my father.”

He said the UK / Irish band’s fans must be “confused”.

The Californian One Direction formed in 2009, have recorded two albums and filed to trademark the name in February 2011.

hey are seeking $1m (€760,000) in damages from Simon Cowell record label Syco, as well as an injunction preventing any further use of the name.