The 35-year-old model and host of the Bravo-turned-Lifetime reality design competition is four months pregnant with her fourth child, E! News sources confirmed Wednesday.
Klum already has two children with her 46-year-old husband Seal -- three-year-old Henry Gunther Ademola Dashtu Samuel and two-year-old Johan Riley Fyoder Taiwo Samuel.
In addition, Seal is also the adoptive father of four-year-old Helene "Leni" Klum, Heidi's daughter from a previous relationship with Italian businessman Flavio Briatore.
Rumors that Klum is once again expecting began when sketches of several redesigned couture gowns she is considering wearing to an upcoming event in which she plans to formally announce her pregnancy surfaced online briefly, In Touch Weeklyreported Wednesday.
The sixth-season of Project Runway -- the first new season of the series to air on Lifetime following a prolonged legal battle between Bravo's NBC Universal parent company, The Weinstein Company, and Lifetime Networks -- it expected to premiere on Wednesday, August 15.