US-MUSIC-GRAMMY AWARDS-SHOW

Rihanna, Bruno Mars, Sting, Ziggy and Stephen and Damian Marley perform in tribute to Bob Marley on stage at the Staples Center during the 55th Grammy Awards in Los Angeles, California, February 10, 2013. AFP PHOTO Joe KLAMAR (Photo credit should read JOE KLAMAR/AFP/Getty Images)

US-MUSIC-GRAMMY AWARDS-SHOW

Rihanna, Bruno Mars, Sting, Ziggy and Stephen and Damian Marley perform in tribute to Bob Marley on stage at the Staples Center during the 55th Grammy Awards in Los Angeles, California, February 10, 2013. AFP PHOTO Joe KLAMAR (Photo credit should read JOE KLAMAR/AFP/Getty Images)

US-MUSIC-GRAMMY AWARDS-SHOW

Rihanna, Bruno Mars, Sting, Ziggy and Stephen and Damian Marley perform in tribute to Bob Marley on stage at the Staples Center during the 55th Grammy Awards in Los Angeles, California, February 10, 2013. AFP PHOTO Joe KLAMAR (Photo credit should read JOE KLAMAR/AFP/Getty Images)

US-MUSIC-GRAMMY AWARDS-SHOW

Rihanna, Bruno Mars, Sting, Ziggy and Stephen and Damian Marley perform in tribute to Bob Marley on stage at the Staples Center during the 55th Grammy Awards in Los Angeles, California, February 10, 2013. AFP PHOTO Joe KLAMAR (Photo credit should read JOE KLAMAR/AFP/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars (L) and Rihanna perform onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars (L) and Rihanna perform onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars and Rihanna onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Singers Ziggy Marley, Bruno Mars and Rihanna onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Singers Bruno Mars, Rihanna and Ziggy Marley onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Singers Ziggy Marley, Bruno Mars, Rihanna and Damian Marley onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars and Rihanna onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars, Rihanna and Damian Marley onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Ziggy Marley, Bruno Mars and Rihanna onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars, Rihanna and Damian Marley onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Ziggy Marley, Bruno Mars and Rihanna onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Singers Bruno Mars and Rihanna onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Singers Ziggy Marley, Bruno Mars, Rihanna and Damian Marley perform onstage during the 55th Annual GRAMMY Awards at STAPLES Center on February 10, 2013 in Los Angeles, California. (Photo by Christopher Polk/Getty Images for NARAS)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Musicians Ziggy Marley, Bruno Mars and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Sting, Ziggy Marley, Bruno Mars and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Ziggy Marley, Bruno Mars and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Sting, Ziggy Marley, Bruno Mars, Rihanna and Damian Marley perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Ziggy Marley, Bruno Mars and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Sting, Damian Marley, Bruno Mars and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Ziggy Marley, Bruno Mars and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Bruno Mars, Ziggy Marley and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Sting, Ziggy Marley, Bruno Mars, Rihanna and Damian Marley perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Sting, Ziggy Marley, Bruno Mars, Rihanna and Damian Marley perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: Musicians Sting, Ziggy Marley, Bruno Mars, Rihanna and Damian Marley perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Musicians Ziggy Marley, Bruno Mars, and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

The 55th Annual GRAMMY Awards - Show

LOS ANGELES, CA - FEBRUARY 10: (L-R) Musicians Ziggy Marley, Bruno Mars, and Rihanna perform onstage at the 55th Annual GRAMMY Awards at Staples Center on February 10, 2013 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)