Some duets just work better than anyone could’ve predicted. We’re looking at the pop pairings whose voices, styles, and energy spark instant magic, from soulful love songs to playful clashes and powerhouse ballads. Our countdown includes unforgettable collaborations from Elton John & Kiki Dee, Sonny & Cher, Marvin Gaye & Tammi Terrell, Beyoncé & Shakira, Lady Gaga & Bradley Cooper, Whitney Houston & Mariah Carey and more!