bass guitar (tracks 1–3, 6, 13–15; guitarrón (track 7), double bass (track 13), acoustic guitar (track 13) Brian "Big Bass" Gardner – mastering Keith Harris – drums, percussion, keys Tal Herzberg – additional engineering (tracks 5 and 13) Jerry Horton – guitar (track 12) Tippa Irie – vocals (track 4) Jun Ishizeki – engineering (track 10) Markus Klinko – photography Chris Lord-Alge – mixing (track 12) John Legend – vocals (track 10) Tony Maserati – mixing (tracks 1–9, 11, 13–15) Sérgio Mendes – piano (track 8) Debi Nova – vocals (track 7) Tim Orindgreff – horns (track 2), saxophone (track 7), flute (track 7) George Pajon – guitar (tracks 1, 3, 5–8, 10, 13 and 15) Indrani Pal-Chaudhuri – photography Chuck Prada – percussion (tracks 7 and 14) Dante Santiago – backing vocals (tracks 1, 3, 4, 6, 10, 14 and 15), vocals (track 7) Noelle Scaggs – backing vocals (tracks 3 and 6) Jacoby Shaddix – vocals (track 12) Christine Sirois – engineering assistance (tracks 1, 5–7 and 13) Taboo – vocals (tracks 1–3, 5–7, 9 and 13) Justin Timberlake – vocals (track 13) Jason Villaroman – engineering (track 11) will.i.am – vocals (tracks 1–10, 12–15), Moog synthesizer (tracks 1, 4, 5, 8–11 and 13), drum programming (tracks 1, 4, 6–10), clavinet (tracks 12 and 13), drums (track 2), piano (track 2), Wurlitzer electric piano (track 4), synthesizer (track 10), executive production, production (all tracks), engineering (tracks 2–4, 8, 9, 12 and 14), mixing (tracks 10 and 14) Terence Yoshiaki – drums (tracks 3 and 7), percussion Charts Weekly charts Year-end charts Decade-end charts Certifications Release history See also Black Eyed Peas discography List of UK R&B Albums Chart number ones of 2003 List of number-one albums of 2004 (Australia) Notes References Bibliography External links Official website 2003 albums Black Eyed Peas albums Albums produced by Ron Fair Albums produced by will.i.am Interscope Geffen A&M Records albums