Credit: John Shearer/WireImage.com

John Travolta and wife Kelly Preston are indeed expanding their family -- but with one baby, not two.

A rep for Travolta, 56, and Preston, 47, slams a new tabloid report claiming that Preston is pregnant with twins. "Totally false," the rep tells UsMagazine.com. "They are not expecting twins."

On May 18, the Hollywood couple announced on their websites: "It's impossible to keep a secret...especially one as wonderful as this. We want to be the first to share this great news with everyone that we are expecting a new addition to the our family."

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Travolta and Preston have a 10-year-old daughter, Ella Bleu. In 2009, their 16-year-old son Jett tragically died of a seizure.