The mourners Wednesday include Sean "Diddy" Combs, Missy Elliott, Q-Tip, LL Cool J, Russell Simmons, 50 Cent and Grandmaster Flash.
The 44-year-old hip-hop mogul was found dead in his Bronx apartment last week with a gunshot wound to the head. The medical examiner ruled it a suicide.
Speaking outside the chapel, Grandmaster Flash said he wished Lighty had reached out to him for help. He says Lighty must have been under "tremendous pressure," adding, "it's really sad."
Lighty was laid out in a dark suit, surrounded by arrangements of white flowers. A slide show depicting his life appeared on a screen.