Motörhead ( /ˈmoʊtərhɛd/) are an English heavy metal band formed in 1975 by bassist, singer and songwriter Ian Fraser Kilmister, professionally known by his stage name Lemmy, who has remained the sole constant member. The band are often considered a precursor to or one of the earliest members of the New Wave of British Heavy Metal, which re-energised heavy metal in the late 1970s and early 1980s. To date, Motörhead have released twenty studio albums, seven live recordings, five compilation albums and five EPs. Usually a power trio, they had particular success in the early 1980s with several successful singles in the UK Top 40 chart. The albums Overkill, Bomber, Ace of Spades, and particularly No Sleep 'til Hammersmith, cemented Motörhead's reputation as one of Britain's foremost rock bands. Motörhead have sold more than 30 million albums worldwide, and 15 million in the United States alone.