Campbell revealed he was going into the session after getting up for the day at 3.30am, as he usually does to host TVNZ's Breakfast programme.
"That's what time I go to sleep!" replied a stunned Melodownz.
Schooling Campbell on kava tradition, the rapper tells him to down his first shell in one go.
The broadcaster gamely steps up to the plate, though admits he was "quite whacked" by just one draught of the popular Pacific beverage.
Campbell admitted that he had forced to make changes to his drinking since he took up his early-morning role, revealing he no longer drinks alcohol five nights a week and saying that it has "made a difference".
As more shells are consumed, the conversation flows and Campbell reveals what drives him as a journalist, keeping the conversation on a stable track despite admitting to feeling "a little stoned".
The chat turns to hip hop, with Campbell sharing his old-school favourites and sharing how the music had played a massive part of opening him up to the world.
The episode is the first in a new series from Melodownz, which will see other special guests drop in to drink a few shells and share their thoughts.
Kava, made from the roots of the piper methysticum plant, has been growing in popularity across New Zealand in recent years.
Increasingly consumed in non-traditional settings, the drink is entirely legal in New Zealand and regulated as a food under the Food Standards Code.
Its popularity has seen more outlets selling the peppery brew, including a kava bar in the heart of Auckland City.
The Four Shells Kava Room opened in 2019 and serves kava in-store and also provides takeaway bottles for those wanting to chill at home.
They've been forced by the recent lockdown to branch out further, now offering a contactless delivery service for inner-city suburbs.
