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Is there anything that makes innocent bystanders cringe faster than a couple fighting in public? Heidi Klum's rebound romance with her bodyguard boyfriend, Martin Kristen, experienced a hiccup on Sunday night when they had a spat at popular Manhattan eatery The Spotted Pig, says the New York Post.

"They had been drinking with a male friend at a table, and things became heated very quickly," relays an eyewitness.

That presumably uncomfortable dining companion was believed to be the model-mogul's pal (and fellow "Germany's Next Top Model" judge) Thomas Hayo, who had to listen to them bicker for an hour before "an upset Klum abruptly walked out of the restaurant alone and stumbled down the block trying unsuccessfully to hail a cab," according to the paper.

The mother of four, who began dating Kristen a few months after calling it quits with Seal, eventually returned to the restaurant "but stubbornly refused to go inside and rejoin [him] at the table," adds the onlooker. Instead, she "stood in the doorway, looking upset."

Kristen finally relented and came to her, but after more "words were exchanged," he hopped in a cab alone. Klum reportedly stayed another hour before leaving via a car service.

"She'd had one drink too many, and they had an argument," shrugs an insider. "All couples have disagreements, but most don't get recognized when they have them."

Then again, Heidi made sure she and Kristen were recognized on Tuesday, when they stepped out smiling and holding hands for an al fresco lunch and shopping expedition (see photo above). The paparazzi were conveniently in tow.

Last month, Klum brushed off engagement speculation sparked by the couple's matching rings.

"I did get a present from my boyfriend. He did give me a ring, and he has the same," she explained. "I am not engaged. I am not planning to get married anytime soon. It's just a beautiful piece of jewelry. Just something nice."


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