In 2001, Chilean rock band La Ley participated in MTV's Unplugged series in Miami, Florida, US. The album MTV Unplugged contains the recordings of the live concert and is to this date the band's best selling album, with sales of 1.5 million copies worldwide. The album emphasizes the band's alt-rock 1990s material rather than their 1980s pop rock sound. Mexican singer Ely Guerra is featured as a guest singer on "El duelo". La Ley is augmented for this appearance with more musicians and a string section.