The 43-year-old Backstreet Boys member called Spears' conservatorship "grotesque" and claimed that the last time he saw her "she just didn’t know who was there."
"Everyone gets so upset, like, ‘Why don’t I talk about it?’” the Good American founder said during the family's reunion with Andy Cohen.
The reality star filed for divorce from her third husband in February.
Kardashian also said that she owes Humphries a huge apology for the way she broke up with him.
The Lip Kit founder also told Andy Cohen why she kept her pregnancy a secret from the "KUWTK" cameras and the general public.
"You teach your children to be polite and be nice to other people and all that kind of stuff, and it does make me cringe a little bit,” McCain told Andy Cohen.
"I really think that she thought she was complimenting us," the "Empire" star told reality-TV producer Andy Cohen.
"She was the one who said, 'Oh, my God, you guys are fabulous, I’m gonna show you around to all the people,’" Richie recalled to Andy Cohen.
The "Big Shot" star shared with Andy Cohen this week how he was "disappointed" with the twins not appearing on the follow-up series to "Full House."
Andy Cohen questioned the "Big Shot" star, recently chosen by People readers as the "Sexiest Zaddy."