The film, featuring Reeves and Alex Winter reprising their titular roles, serves as a follow up to 1989's "Bill and Ted's Excellent Adventure", and "Bill and Ted's Bogus Journey", released in 1991.
According to Deadline, details of the 35-year-old's role are being kept under wraps. The "Day 'N' Night" hitmaker will also star alongside Brigette Lundy-Paine and Samara Weaving, who will portray Bill and Ted's daughters.
The Grammy winner, born Scott Mescudi, has previously appeared on screen in "Need for Speed" and the film version of "Entourage". His TV credits include "How to Make It in America", "Brooklyn Nine-Nine" and "One Tree Hill".
The time-travelling buddy comedy will be directed by Dean Parisot while the original writers of the hits, Chris Matheson and Ed Solomon, will return to pen the third film in the beloved series.