Bronny James, the eldest son of NBA superstar LeBron James, is in stable condition after suffering a cardiac arrest during practice with his college basketball team, the James family said on Tuesday.

Bronny James, 18, collapsed on court while training with his University of Southern California team-mates on Monday in Los Angeles.

"Yesterday while practicing Bronny James suffered a cardiac arrest," a spokesperson for the James family said in a statement to AFP.

"Medical staff was able to treat Bronny and take him to the hospital. He is now in stable condition and no longer in ICU.

"We ask for respect and privacy for the James family and we will update the media when there is more information.

"LeBron and Savannah wish to publicly send their deepest thanks and appreciation to the USC medical and athletic staff for their incredible work and dedication to the safety of their athletes."

The TMZ.com celebrity news website reported that James was unconscious before being rushed to hospital following the cardiac incident.

The James family meanwhile were given words of support from NFL player Damar Hamlin, who suffered a cardiac arrest while playing for the Buffalo Bills in January in an incident that shocked the sports world.

"Prayers to Bronny & the James family as well," Hamlin wrote on Twitter.

"Here for you guys just like you have been for me my entire process," added the 25-year-old, who subsequently made a full recovery and has since been cleared to resume his NFL career.

Los Angeles Lakers legend Earvin "Magic" Johnson also offered support. "We are praying and hoping he makes a full and speedy recovery," Johnson wrote on Twitter.

Bronny James committed to playing for the USC Trojans in May after becoming one of the top prospects in US high school basketball.

He capped a stellar senior year campaign at the exclusive Sierra Canyon school in Los Angeles with 15 points in an all-star game of top college candidates, sinking five 3-pointers.

His famous father — the NBA's all-time leading scorer as well as a four-time NBA champion and four-time NBA Most Valuable Player — has long spoken of his desire to extend his career in order to play in the league with his son.

"I need to be on the floor with my boy, I got to be on the floor with Bronny…that would be ideal for sure," James told ESPN in an interview in January.

Teen star James could be eligible for the NBA Draft after one season for the Trojans, who are expected to have a strong squad next season.

Some analysts have already marked James as a likely top-10 selection in the 2024 NBA Draft.

Bronny James would turn 20 in October of 2024, the same month that the 2024-25 NBA campaign will start. His father would turn 40 in December of 2024.