Sources confirm that the couple's new baby is due in the 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 fiancée's little girl.
Seal prides himself on playing the proud papa – from celebrating with champagne at the New York City hospital where Klum, 31, gave birth last May to dedicating his latest album, Best: 1991-2004, first to "my daughter Leni," then to Klum and her parents. Says a pal: "He is crazy about Leni, he is always carrying her around. He is the first one to change a diaper."
The never married singer – who has no other children – is obviously committed: The day before Christmas Eve he proposed to Klum atop a Canadian mountain, and the couple have purchased a $4.3 million Bel-Air estate.
In a statement released by the couple on Friday, March 18, they said of Klum's pregnancy: "There is nothing that gives us greater happiness than the realization of our dream."
And when will they finally seal the deal? "I would say they'll be married within a couple of months," says a source. "He takes it very seriously. Heidi and the baby come first." Make that the babies.