Once the Four Seasons became a consistent success, Frankie Valli established a side career doing solo recordings whose style harkened back to pre-rock pop. The best and most successful example of his solo work is “Can’t Take My Eyes Off You,” a swinging ballad that would be perfectly at home on one of Frank Sinatra’s mid-1950's albums. The lyrics are a pledge of romantic devotion played out in a style that mixes raw emotion with lounge-singer savoir faire: “At long last love has arrived/And I thank God I’m alive/You’re just too good to be true/Can’t take my eyes off you.” The music skillfully blends ballad and pre-rock pop feels by wedding gentle, yearning verses that ebb and flow in a cocktail jazz style to a swinging chorus that bounds along on a series of surging, soaring melodic motifs. Frankie Valli’s recording of “Can’t Take My Eyes Off You” starts in a ballad style with stately horns drifting a smooth, jazzy beat, undergoes a change midway through where the horns and the beat both start to swing in an uptempo, lounge music style and then shifts back and forth between these two feels for the rest of the song. Valli navigates this tricky set of tempo shifts with graceful style, using a silky tenor croon for the lighter moments and a swaggering baritone in the uptempo moments. It all added up to a swinging ballad with a beat that became a #2 smash hit and an instant standard that was extensively covered by MOR kingpins like Andy Williams, Paul Anka and Englebert Humperdinck. Since then, “Can’t Take My Eyes Off You” has become an oldies radio favorite and has popped up in films as diverse as The Deer Hunter and Conspiracy Theory.