Heidi Klum is revealing her secrets on how she keeps her marriage to Tom Kaulitz spicy. "I mean we were just lingerie shopping," the supermodel, 52, tells PEOPLE exclusively ahead of her much anticipated return to Project Runway on July 31.

Heidi Klum didn't hold back while candidly discussing her 17-year age gap with her husband, Tom Kaulitz. “When our door closes at home, I don’t really care so much what happens around us,” Klum, 52, told People about the backlash they've faced for their age gap in an interview published on Monday,

Heidi Klum, 52, said "my kids don't know me any other way" when asked about critics of her decision to model underwear with her 21-year-old daughter.

Heidi Klum opens up to PEOPLE about her parenting philosophy, backlash about modeling alongside daughter Leni, 21, in lingerie and more in our exclusive cover interview.

You probably know that Heidi Klum has four children. She shares Leni with ex Flavio Briatore, and she shares Henry, Johan, and Lou with another ex, the one and only Seal.