What makes a couple hot? It’s the spark that ignites when they are together and the way their connection touches everyone around them. These 10 dynamic duos had that special something in 2009.

Ed Westwick and Jessica Szohr

What would bad boy Chuck Bass say? More than a year after their romance blossomed on the Gossip Girl set, British actor Ed Westwick, 22, and Jessica Szohr, 24, are still happy together. The glamorous pair were recently seen partying with the cast of New Moon after the film’s New York premiere. “When two people that you know separately get together, you're always like 'Oooh, what's that about?'” co-star Amanda Setton told People. "They really balance each other. I'm just happy that they're happy."

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Sophia Bush and Austin Nichols

Their scenes together on One Tree Hill sizzle — and appear to have brought Sophia Bush and Austin Nichols back together in real life, too. “For some reason there's this It factor,” Austin, 29, told MTV about his chemistry with Sophia, 27. “There's just this really great energy there.” And they aren’t just hot, they’re sweet too. Over Thanksgiving, Sophia and Austin visited American troops stationed overseas as part of the USO tour.

 Zac Efron and Vanessa Hudgens

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First love rarely lasts, but High School Musical’s real-life couple Zac Efron and Vanessa Hudgens still make 2009’s hottest couple list after three years together. In October, Zac, 22, and Vanessa, 21, who are both working on separate projects in Canada, looked wholesome and happy cheering for the home team at a Vancouver Giants hockey game. (The Giants won.) “He’s hot,” Vanessa admitted to Ellen DeGeneres about the boyfriend she rarely talks about and also revealed that he’s a “good” kisser. “Vanessa just brings a sparkle to everything,” Zac confessed to People.