US President Barack Obama called NBA player Jason Collins on Monday to praise his courage after he became the first star in big-time American professional team sports to come out as gay.

Collins, currently a free agent who has played for six teams over 12 seasons, made the announcement in a blockbuster article in Sports Illustrated.

"The President called Jason Collins to express his support and said he was impressed by his courage," said a White House aide, on condition of anonymity.

Obama, a huge basketball fan and keen amateur player, was responsible for ending the ban on gays openly serving in the military, and last year said he believed gays and lesbians should be allowed to marry.

Earlier, the president's spokesman Jay Carney said that the White House saw the revelation by Collins as another example of the progress being made towards gay rights in America.

In the article, Collins declared: "I'm a 34-year-old NBA center. I'm black and I'm gay."

"I didn't set out to be the first openly gay athlete playing in a major American team sport. But since I am, I'm happy to start the conversation."