It’s easy to think that since Santana made his big comeback using a lot of contemporary pop stars it would become the formula for the artists of yore to edge their way back into the limelight. Sergio Mendes, the best-selling Brazilian recording artist of all time, hasn’t made a platter in eight years. He plays piano on a Black Eyed Peas track — “Sexy” from Elephunk — and the jam’s a smash. Will.i.am of the Peas decides to hook up for a full-on collaboration with Mendes, because he’s a huge fan. Being the hotshot producer of the moment, will.i.am recruited everyone from Q-Tip, Justin Timberlake, and John Legend to Jill Scott, Black Thought (the Roots), and Stevie Wonder (just to name a few) to sign on. Recorded in both Brazil and the House of Blues in Encino, the set revisits many Mendes and Brazilian songbook classics and reworks them in the modern beat-driven idiom. Needless to say, the end result is entertaining, if mixed. Let it be said that a cut like “Mas Que Nada” should never have been covered, let alone redone. But it is here with Black Eyed Peas and some backing vocals with, of course, Mendes playing that trademark piano riff. OK, “That Heat” is a reworking of “Slow Hot Wind,” the Henry Mancini tune Mendes covered and is supposedly the first track will.i.am ever sampled at the ripe old age of 14. Here Erykah Badu croons in a sultry humid way as will.i.am goes down deep with the rap. Mendes’ piano is what keeps the thing from falling completely apart. Better is the Baden Powell-Vinicius de Moraes medley of “Berimbau/Consolacao.” Mendes’ Rhodes offers the vamp that the elegant chorus singers — Gracinha Leporace, Debi Nova, and Kleber Jorge — and Mendes groove to. Will.i.am lays down some rather organic-sounding electronic percussion that sounds like palmas, and Wonder blows his harmonica over the entire proceeding as Jorge’s guitar strides alongside Mendes’ piano. This may be the best cut on the set. There is a fine case to be made for the humor in “The Frog,” written by João Donato, and originally covered by Mendes. Q-Tip lays down a charming rhyme and Mendes’ Wurlitzer work is killer. The cover of “Let Me” is stiff and Jill Scott, as fine a singer as she is, doesn’t cut it here, and neither does the rhythm track. The smoother than smooth “Please Baby Don’t,” written and sung by John Legend, works because of Legend’s understanding of Brazilian rhythm and Mendes’ piano groove that carries the voice. “Samba da Bencao,” with Marcelo D2 and guitars by the Maogani Quartet, is engaging; Mendes’ acoustic piano solo is beautiful, as are the horn charts. The title track with India.Arie is simply beautiful. Aire, with backing vocals by Nova and Leporace and a slinky guitar part by Jorge, makes the tune simply float as Mendes decorates it with Rhodes and synth. Timeless is a mixed bag, but it’s not because of Mendes. His own playing and arranging is utterly elegant. As a producer, will.i.am means well and in general does a fine job — though he is, as would be expected, a tad overzealous in working with one of his idols. Timeless may not actually achieve that status, but for the moment it’s a fine effort that doesn’t reek of cloying commercial manipulation and feels like a true collaboration. – Thom Jurek