Diddy said in a statement that he was "heartbroken by the passing of my dear friend."
"He was a wonderful human being, who inspired and paved the way for a Hip Hop generation," the statement said. "We were like brothers - I will miss him more than words can express."
A private funeral for the rap legend will be held at the historic Grace Baptist Church in Mount Vernon, just north of New York City.
Heavy D, born Dwight Arrington Myers, died at a Los Angeles hospital last week after collapsing outside his home. He was 44.
The New York-born rapper was the titular member of Heavy D and the Boyz, which had hits with "Now That We Found Love," "Who's the Man" and "Somebody for Me." He was one of the genre's top stars in the late 1980s and early 1990s.
BET also announced Monday that the Soul Train Music Awards in Atlanta will pay tribute to Heavy D, with Kurtis Blow, Naughty by Nature, Big Daddy Kane, Doug E. Fresh, DJ Eddie F, Whodini and Daddy-O of Stetsasonic participating.
Heavy D's family has launched the Heavy D and Xea Myers Fund, named in honor of the rapper and his daughter, who's 11 years old. The family said it was devastated by his death.
"Though Hev will most notably be remembered for his work both behind-the-scenes and in the forefront, he will always be remembered by us as a generous soul who remained humble and unselfish till his final days," the family said in a statement.
Mary J. Blige, who started her career on Uptown Records, the label on which Heavy D released most of his music and of which he eventually became president, called the late rapper an "angel and protector."
"He was one of the people in my life who always had something inspiring and encouraging to say," she said in a statement. "He was so joyful and optimistic. ... His talent brought so much joy to our lives. I love you and miss you, Heavy."