Billie Paul Piper (born Leian Paul Piper; 22 September 1982), is an English singer and actress. Born and raised in Swindon, Wiltshire, she made her entertainment debut in Scratchy & Co. (1998), and at the age of fifteen signed a recording contract and released her debut single "Because We Want To", which debuted at number one in the UK, making Piper the youngest artist ever to debut at number one. The single was followed by Piper's album Honey to the B (1998), which was certified double platinum by the Recording Industry Association of New Zealand (RIANZ) and platinum by the British Phonographic Industry (BPI). In 2000, Piper released her second album, Walk of Life. In 2003, Piper retired from the recording industry and launched a highly successful television career.

Piper's transition into acting began in 2004. Her most famous role is as Rose Tyler, companion to The Doctor, in the television series Doctor Who on BBC from 2005 to 2006, a role she reprised in 2008, 2010, and 2013. In 2007, Broadcast magazine listed Piper at no. 6 in its "Hot 100" list of influential on-screen performers; she was the top woman on the list. From 2007 until 2011, she starred as the high-flying escort Belle de Jour in the TV series Secret Diary of a Call Girl. She currently stars as Brona, an Irish immigrant, in the horror TV series Penny Dreadful.