Both of the outgoing judges have been with America's Got Talent since season 8, when Klum replaced Sharon Osbourne and Mel B became the show's fourth judge, after only having three judges previously.
A source close to the AGT production tells ET that NBC simply wanted to "change things up," adding there wasn't any particular reason for swapping out Mel B and Heidi Klum as judges.
"It was a network decision. The show does well because it has no problem adding new people and making changes," the source adds. "Also, Heidi, Mel B and Tyra [Banks] have major projects coming up that they need to focus on. There was no drama."
Banks will also be departing as the host, with Terry Crews stepping into her shoes. The job should be an easy transition for Crews, as he's currently serving as the host of America's Got Talent: The Champions.
On AGT: The Champions, Crews recently made headlines for using his Golden Buzzer to send through sand artist Kseniya Simonova to the finals.
"Let me tell you something, I have never been more impressed by the ability to move people the way you did today!" Crews told Simonova before pressing the button and sending a flurry of golden confetti around Simonova, which brought her close to tears.
In October, Crews spoke with ET's Denny Directo about hosting AGT: The Champions, explaining that he didn't look to either Nick Cannon or Banks for advice before taking the prestigious gig.
"You know what, I specifically did not try to get any pointers from Nick or Tyra," he shared. "They're both good friends of mine, but I wanted to bring what I was going to bring, you know what I mean? I was like, I'm gonna pop my pecs, you can't tell me not to pop my pecs."
Nevertheless, he did admit that the pair showed him how to perfect the hosting role. "They did teach me about watching," he said. "I learn from them because I really wasn't ready years ago."
Season 14 of America's Got Talent will likely debut this summer. Watch the video below for more on Crews' hosting skills: