Producer Brian Burton, better known as Danger Mouse, arrived in London in 2001 from Athens, Georgia and soon after began working with Lex on a series of releases that came to define the sound of the label in its early years. Danger Mouse’s breakthrough came with the illicit mash-up long-player, the Grey Album (2004). Lex ran the campaign for the album which proved to be the high-water of the mash up craze.

In the months that followed Danger Mouse recorded the debut Gnarls Barkley record with Cee-Lo and produced the Gorillaz album Demon Days. Both albums included massive hit singles and went multi-platinum.

Danger Mouse has released six studio albums with Lex: Ghetto Pop Life (2003) with Jemini; DANGERDOOM The Mouse & The Mask (2005) with MF DOOM; Gnarls Barkley St Elsewhere (2006) with Cee-Lo; Gnarls Barkley The Odd Couple (2009); Dark Night Of The Soul (2010) with Sparklehorse & David Lynch; and Rome (2011) with Daniele Luppi, Jack White & Norah Jones. He also contributed production to Prince Po's debut album The Slickness (2004).

He has won 3 Grammy Awards and had 9 nominations for Lex albums. The wins include Producer of the Year in 2011 for Dark Night of The Soul and one each for the Gnarls Barkley single Crazy and album St Elsewhere.