Did Mario go out and make out with Karina Smirnoff?

Is Mario really going out with Karina?

Mario was in full-on denial mode about his off-camera relationship with Karina Smirnoff last night at Crustacean in Beverly Hills, where several of the "Dancing With the Stars" contestants -- past and present -- went for a late group dinner.

Alec Mazo strolled in with his wife, Edyta Sliwinska, who was wearing either the shortest dress on theplanet -- or the longest top. There may be cut-off shorts hiding under there. Also on the scene: Kym Johnson, wearing a veeeery low-backed black dress that showed off a glimpse of her tan line. At least, it looks like a tan line. Could it be a thong?

And this season's steamy dancing duo  --  Karina and Mario -- arrived together, but not holding hands. So was it a date?

Click here to see  Mario talking about their "not dating" and their alleged recent make-out session.

"We have naturally good chemistry," Mario told Access Hollywood's cameras. "But it's all professional."

So were they really caught making out? "If hugging or saying goodbye to someone is making out, what is this world coming to? We were definitely not making out."

Uh-huh. And that's probably why the camera also caught Mario later singing a song -- right to Karina -- causing her to blush and turn away. Just watch that video and decide for yourself.

C'mon, you guys are so busted!

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Photos: Karina Smirnoff and Mario, left. Kym Johnson, center. Edyta Sliwinska and Alec Mazo. WireImage