Grim: Lamar Odom, pictured in New York earlier today, is said to be 'devastated' at news of the boy's death
The boy underwent emergency surgery in New York City after yesterday's crash, but died this morning, according to TMZ.
A funeral for him was held today, with the website reporting that Lamar is 'devastated' at the tragedy.
The accident happened after the vehicle, driven by a car service employee, collided with a motorcyclist.
The bike then propelled into the 15-year-old pedestrian who was taken to hospital with severe injuries.
Odom, 31, who looked grim as he headed out into the city earlier today, was said to be returning from a trip to the barbershop when the accident happened.
According to reports, the Los Angeles Lakers star, who was uninjured, was particularly upset after the crash took place and was seen crying at the scene.
Odom, is reported by the New York Post to have been travelling in the back seat without his wife Khloe Kardashian in the Queens area of the city.
The basketball player and reality show star is visiting the Big Apple to attend his cousin's funeral.
Earlier toady, he tweeted: 'Thank you for your support and prayers!' after being spotted out in New York with Khloe.
Brave face: Khloe Kardashian joined her husband Lamar to run errands in the city earlier today
'My heart/soul goes out 2every1 in pain from any suffering,' she wrote. 'Pray 4all of the angels surrounding us constantly. May our spirits stay strong.'
This was followed by several choice quotations from the bible, after seemingly getting angry at some comments directed at her on the social networking site.
Prayer: Khloe tweeted that her 'heart goes out to everyone in pain from any suffering'
She added that the comments were making her 'think twice about social media.'
'A family member of his (Lamar) was killed and some of the comments you are saying due to the fact I am off twitter today are disgusting.'
Sad news: The star was said to be distraught at the scene of yesterday's tragic accident