As Kramer and George (of Seinfeld fame) discovered when they tried to sell “rare” records, Sergio Mendes isn’t always taken seriously these days. The Brazilian achieved U.S. stardom for his jet-set pop in the 1960s, met with fleeting success again in 1983, and was rediscovered by fans of lounge music in the mid-’90s. An album Mendes released in 1996 actually contained a rap song and, surprisingly, 45 years after his debut, his new album embraces hip-hop and neo-soul unabashedly. Is he sincere or jumping on a bandwagon in a bid for a hit? The guest list indicates that he’s serious. Timeless features big names, including Erykah Badu, Stevie Wonder, Jill Scott, indie.arie, John Legend, Q-Tip, and Black Thought of the Roots. The lead-off track is “Mas Que Nada,” Mendes’ first U.S. hit, this version featuring the Black Eyed Peas, the group’s will.i.am appearing on six tracks as well as being the album’s producer. Once one makes the leap of faith and accepts the apparent incongruity of mixing airy Brazilian pop with hip-hop, some of which is politically charged, the album becomes enjoyable.