Diddy and Usher were among the celebrities in attendance, and the Rev. Al Sharpton delivered a message for his young daughter, which he said was directly from President Barack Obama.
Sharpton read briefly from the note for 11-year-old Xea Myers; it offered the young girl words of encouragement. She also spoke, and told the packed church that her father was "still here, not in the flesh, but in the spirit."
Heavy D died last week in Los Angeles at the age of 44. His family said the death was due to complications from pneumonia.
Heavy D, whose real name was Dwight Myers, was influential in the development of rap. His hits included "Now That We've Found Love" and "Nuttin' But Love."