The name was originally used among early Christians in honour of the saint, as opposed to the classical character. In England it was commonly spelled Ellen during the Middle Ages, and the spelling Helen was not regularly used until after the Renaissance. A famous bearer was Helen Keller (1880-1968), an American author and lecturer who was both blind and deaf.
Already growing in popularity due to Australian model Elle Macpherson (1964-), this name received a boost in the United States after the release of the 2001 movie Legally Blonde featuring the main character Elle Woods. In the United Kingdom the name was already fairly common at the time the movie came out, and it actually started declining there shortly afterwards. A famous bearer is American actress Elle Fanning (1998-).