Combs is expected to deliver a eulogy, but a website has reported that the rapper is so heartbroken about Porter's untimely death at age 47 that he might not be able to speak.
Singer Faith Evans is set to perform and other celebrities are attending the funeral which will feature an incredible group of more than a thousand mourners.
Porter will be buried next to her mother, who died in 2014.
Porter never married Diddy, 49, but was the mother of his 11-year-old twins Jessie James and D'Lila. Porter and Diddy also shared son Christian, 20. Porter also had a 27-year-old son, Quincy.
As RadarOnline.com reported, Diddy attended Porter's wake on Friday night, as did Kimora Lee Simmons and her husband Tim Leissner.
Before she passed away last week, Porter reportedly had complained she was suffering from the flu.
She was found dead in bed the next day on November 15. Supposedly she perished from cardiac arrest.
However, her death at such a young age at her Toluca Lake, Calif. home remains a mystery.
Radar learned Porter's "cause of death was deferred" by the Los Angeles County Coroner's Office. Officials said additional tests needed to be performed but her body was released.
Diddy and Porter had an on-again, off-again relationship which lasted from 1994 to 2007.
The music mogul attended a private viewing of her body before her Georgia funeral today.
"I don't know what I'm going to do without you baby.I miss you so much," Diddy has said on social media.
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