After telling ET that marriage plans were "in the works," New Kids on the Block's Jonathan Knight made it official by proposing to longtime boyfriend Harley Rodriguez.

Knight confirmed his engagement to Jenny McCarthy -- who's married to NKTB's Donnie Wahlberg -- while on her SiriusXM radio show on Tuesday. "We were in Africa, our parents were there -- our moms were there -- and I just figured this was the time to pop the question," the 47-year-old singer explained, adding that Rodriguez had "no clue" about the proposal. "We've always considered ourselves a married couple."

WATCH: New Kids on the Block to Appear on Fuller House, Cast Adorably Geeks Out

Knight had been planning the engagement weeks ahead of their African safari. “We were on the Zambezi river, it’s right above Victoria Falls. We took a nighttime raft dinner, just the four of us out on the river. There was a hippopotamus in the background,” he described. “It was a super moon. It was just absolutely beautiful, it was so romantic.”

Knight and Rodriguez started dating in 2008, and while they've yet to tie the knot, they have taken each other’s names on social media. "We were rehearsing the day I met him," Knight recalled during an interview with ET in June. "He’s a trainer at Barry’s Bootcamp, so I would be with the band all day, then the only time I got to see him was to go take his class. I’d take his class then we’d go for dinner afterwards."

WATCH: New Kids on the Block's Jonathan Knight Talks About Hiding His Sexuality As a Teen

Knight added, "He’s been around from the beginning and seen [NKOTB’s comeback] morph into what it is today."

This exciting news comes after the boy band shared on Tuesday that they'll be touring this summer with Boyz II Men and Paula Abdul. Tune in tonight for ET's exclusive interview with NKOTB, which occurred moments after their big announcement.