Chasez, along with fellow 'NSYNC members Justin Timberlake, Lance Bass, Joey Fatone and Chris Kirkpatrick, took the stage twice with Jackson in 2001. Their first meeting came at the MTV Video Music Awards, while performing the band's song "Dirty Pop." Near the end of the number, Jackson emerged from behind the stage for a surprise cameo to the delight of the audience.
"It was amazing," Chasez told MTV News. "The rehearsal was kind of the most bizarre part, and all of a sudden, he starts dancing and everybody forgot to dance. It was one of those moments where you were always watching him."
Later that year, for the "Michael Jackson: 30th Anniversary Special," the ensemble duetted with the reunited Jackson 5 on "Dancing Machine."
Now, as a judge on "ABDC," Chasez sees the impact Jackson continues to have on the next generation of performers.
"Obviously, we had a whole show dedicated to Michael, and we also did a show that was all about Janet as well, and the Jackson impact — you're talking about what Bach is to classical music. That's what Jackson is to pop."
Check out everything we've got on "Michael Jackson's This Is It."