11-year-old Kyle Glover, Usher's ex-wife Tameka Foster's son, is said to be in a critical condition following a collision at Lake Lanier in Georgia yesterday (July 7).
E! reports that Glover and an unidentified 15-year-old girl were sitting in an inner tube being pulled by a boat, when they were struck in the head by a jet ski being driven by a 38-year-old man.
According to Department of Natural Resources Sergeant Mike Burgamy, the pair were air-lifted to Children's Healthcare at Egelston Hospital in Atlanta for urgent treatment.
Usher and Foster are currently engaged in a custody battle as part of their divorce, but the singer is said to have chartered a private jet for his ex to fly to her injured son's side.
As the news broke, friends of the 'Climax' star posted messages of support on Twitter.
Music mogul Russell Simmons tweeted: "Praying that Usher and Tameka's son is ok..." along with a link to the story.
"Everyone PLEASE pray for Usher and Tameka's son! This is the time they really need your prayers!" added former American idol contestant Fantasia Barrino.
Further details are yet to emerge, but Burgamy is said to have told Atlanta TV station 11 Alive that it is too early to tell if any charges will be filed and that alcohol was not a factor in the accident.