· Rihanna has signed up to be the face of Gucci’s upcoming “Tattoo Heart” campaign for children’s charity UNICEF. Launching in December, the ad campaign will feature the singer sporting a line of limited-edition Gucci products. · The next season of “American Idol” will feature more instrument-playing contestants, fewer audition shows with terrible singers and more half-hour result nights. Auditions for the eighth season begin this week in the San Francisco area. · The final hearing in Britney Spears ‘ child-custody case was supposed to take place today, but the court date has been delayed until Friday to give ex-husband Kevin Federline ’s attorney, Mark Vincent Kaplan, more time to prepare. Kaplan denied, however, that the delay was tied to a possible settlement in the long-simmering case. · Nas is hitting the road this summer with The Jones Experience a tour that will feature the “Hero” MC performing in small clubs across North America with Talib Kweli , Jay Electronica and DJ Green Lantern . The 21-date tour kicks off July 22 in Montreal and ends September 5 in Minneapolis. · Fresh from her appearance at the Miss Universe pageant , Lady Gaga is slated for more prime-time perversity on the July 17 “So You Think You Can Dance” elimination show , where the singer will perform “Just Dance.” · First Supergrass ‘ Gaz Coombes had to fill in for Dave Grohl for a song at the recent VH1 Rock Honors , and now the Foo Fighters have been forced ...