The late "Juicy" hitmaker was shot and killed in Los Angeles on March 9, 1997 and on Saturday, March 9 Combs took to social media to honour him.
"There will NEVER be another," he wrote alongside a picture of himself and the rapper. "The GREATEST RAPPER OF ALL TIME. Today we celebrate and honor you king. Love and miss you!!!!!!!!! Happy Biggie Day!".
"BIGGIE SMALLS IS THE ILLEST (best)!!!!! HAPPY BIGGIE DAY!," he added alongside a video of them performing onstage.
The rapper, real name Christopher Wallace, was 24 years old at the time of his death. His murder remains unsolved.