The pregnant supermodel shoots down stories that she and the father-to-be have secretly hitched

Despite press reports in her native Germany that Heidi Klum has secretly married British pop star Seal, with whom she is expecting a child, the supermodel shot down the stories on a German TV show over the weekend.

Showing off her engagement ring on the popular program Wetten Das? (loosely translated, Wanna Bet?), Klum declared twice that she has not made it legal with Seal.

“Look I still have one ring,” she said. “There are not two rings on my hand yet.”

Show host Thomas Gottschalk later asked if she read press reports about herself. “Often, yes, I read what is written,” she replied, prompting him to inquire: “What if the headlines declared, ‘Heidi Klum marries Seal’?”

Laughing before turning serious, she answered: “Thomas, I already told you. We did not marry. So the story would be false.”

Describing her relationship with Seal, she said: “We all sing a lot together. I sing a lot, even with my voice.”

Last week, PEOPLE reported that Klum, 31, and Seal, 42, are expecting, with sources confirming that the baby will arrive this fall. “They are thrilled,” says a pal. “They have created a nontraditional family unit.”

That family includes Klum’s 10-month-old daughter, Leni, whose father is 54-year-old Italian businessman Flavio Briatore. But from the beginning of Seal and Klum’s romance – which began in February 2004 before Klum gave birth – the singer has taken up fatherly duties for his fiancee’s little girl.

Says a pal: “He is crazy about Leni, he is always carrying her around. He is the first one to change a diaper.”