(Photo by Slaven Vlasic/Getty Images)NEW YORK, NY - APRIL 26: Peter Hermann and Mariska Hargitay attends the 'Leap Of Faith' Broadway Opening Night at St. (Photo by John Lamparski/Wire Image)NEW YORK, NY - JUNE 06: August Hermann, Peter Hermann, Mariska Harigtay and daughter Amaya Hermann attends the 2012 Baby Buggy Bedtime Bash hosted by Jessica And Jerry Seinfeld on June 6, 2012 in New York City.(Photo by Gary Gershoff/Wire Image)NEW YORK, NY - SEPTEMBER 22: Mariska Hargitay (L) and Peter Hermann attend the 'Hotel Transylvania' premiere at the Academy Theater at Lighthouse International on September 22, 2012 in New York City.(Photo by Jim Spellman/Wire Image)NEW YORK - OCTOBER 15: Actress Mariska Hargity and husband Peter Hermann attend the 2008 Princess Grace Awards Gala at Cipriani 42nd Street on October 15, 2008 in New York City.(Photo by Matthew Peyton/Getty Images)NEW YORK - OCTOBER 26: Peter Hermann and Actress Mariska Hargitay attend the Joyful Heart Foundation Dinner at Bon Appetit Supper Club and Cafe on October 26, 2008 in New York City.
“There is no secret,” Hermann, 50, told ET during a sit-down interview with Hargitay to promote his new children’s book, .
(Photo by Astrid Stawiarz/Wire Image for Niche Media) NEW YORK, NY - DECEMBER 04: Mariska Hargitay and Peter Hermann attend the 'War Horse' world premiere at Avery Fisher Hall at Lincoln Center for the Performing Arts on December 4, 2011 in New York City.
(Photo by Steve Mack/Film Magic)NEW YORK, NY - MAY 23: Actor Peter Hermann, actress Mariska Hargitay with their baby girl, Amaya Josephine attend the 20th Annual Playground Partners Family Party at Central Park, Heckscher Softball Fields on May 23, 2012 in New York City.
(Photo by Jim Spellman/Wire Image)HOLLYWOOD, CA - NOVEMBER 08: Actor Peter Hermann, son Andrew, daughter Amaya, actress Mariska Hargitay and son August attend Mariska Hargitay's Star ceremony on The Hollywood Walk of Fame held on November 8, 2013 in Hollywood, California. Ortega/Getty Images)NEW YORK, NY - NOVEMBER 12: Actor Peter Hermann and actress Mariska Hargitay attend the premiere of 'Philomena' hosted by The Weinstein Company at the Paris Theater on November 12, 2013 in New York City.
(Photo by Ben Gabbe/Film Magic)NEW YORK, NY - SEPTEMBER 4: Mariska Hargitay and her husband Peter Hermann attend the match between Roger Federer of Switzerland and Gael Monfils of France during Day 11 of the 2014 US Open at USTA Billie Jean King National Tennis Center on September 4, 2014 in the Flushing neighborhood of the Queens borough of New York City.