Sian Evans (born 9 October 1971) is a Welsh singer. Throughout the 2000s, she was known for being a front woman and singer-songwriter of the band Kosheen, a trip-hop/drum & bass group that, during that decade, placed two albums within the Top Ten of the UK Albums Chart. She has also joined a list of Welsh artists to have topped the UK singles chart with collaboration on the track 'Louder' with DJ Fresh.