Olivia Wilde: 'Cool It' with the Justin Timberlake Talk

04/05/2011 at 09:45 AM EDT

Is a relationship between Justin Timberlake and Olivia Wilde heating up? Not according to the House, M.D. star.

"Cool it, honeybadgers," Wilde, 27, Tweeted Monday, apparently referring to reports that she and Timberlake were seen snuggling at an L.A. nightclub. "We are just friends and have been for years."

The two, who costar in the upcoming sci-fi movie Now, were spotted on Saturday at The Roxbury in Hollywood, where they were apparently getting cozy in a VIP section before moving to the patio so Timberlake, 30, could listen to hip-hop.

While some source say the newly single actress and Timberlake appeared to be a on a date, another source tells PEOPLE: "They've been friends since they worked together on Alpha Dog. Nothing's going on. They're just friends."

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