"We are best of friends. We are really close. We are great co-parents," the actress said, adding, "We really figured out the formula to staying a family."
The Duchess of Sussex recently shrugged off criticism she has gotten for working so much since she and Prince Harry quit their royal duties and moved to the US.
The couple, who have a 44-year age difference, met in 2014 while Jagger was on tour with the Rolling Stones in Japan, where the ballerina had been traveling.
Schwarzenegger recalled Champion "nagging" him about the plot "nonstop" when he booked his Season 3 role as Saxon Ratliff, but he "didn't tell anybody."
Appearing on the "Whine Down with Jana Kramer" podcast, King shared her "scary" reality after her ex-husband was granted full physical custody of their two sons.