Del Marquis (born Derek Gruen on August 31, 1977) is an American musician and the lead guitarist for the U.S. group, Scissor Sisters.
Born in New York City, he was introduced to the Scissor Sisters in 2001 at the insistence of a friend who, at the time, was dating Jake Shears. He originally dismissed the band when he first saw them perform at The Cock, a New York City gay bar. His subsequent membership of the Scissor Sisters is mainly due to his late reappraisal, and is primarily owed to his reply to the band's advertisement in a newspaper for a guitarist.
Unlike the outrageously flamboyant stage image of Jake Shears and Ana Matronic, Del Marquis possesses an image on stage much like that of Paddy Boom and Babydaddy.
According to Del Marquis' own account on the band DVD, he has admittedly stalked several renowned guitarists, doing so by sleeping outside their hotels. One of these was Robert Smith of The Cure.
Del has produced the DVD, Kuvaputki released in 2008.
On Halloween 2008, he began releasing solo material, starting with the song "Hot House Shadow," only available with a digital film from his official site. The video was made by Embryoroom, the same team who made Kuvaputki. Further to this, on November 6 it was announced that Del was to digitally release a series of solo EPs, with one to be released the first Tuesday of every month from December 2008 to April 2009. These will contain collaborations with Joan As Police Woman and Basement Jaxx. The first EP, titled "Hothouse," was released on December 2. The "Runaround" EP will be released in September 2009, and includes remixes from Baron von Luxxury and Lifelike.
Del appeared as a guest vocalist and guitarist on the October 2009 single "I'll Sing Like Billy MacKenzie in Heaven" by Portland, OR electronic pop group Microfilm.
Del Marquis is included on a list of openly gay entertainers in The Advocate's "Forty under 40" issue of June/July 2009.
Marquis is of Latvian descent, and his grandfather was born in Riga.