Russia's richest man says he has bought James D. Watson's Nobel Prize medal at Christie's in order to return it to the scientist.

Nobel Prize auction James Watson DNA

James Watson won the Nobel Prize in 1962 for his role in the discovery of the structure of DNA. (Christie's/The Associated Press)

​Alisher Usmanov, a metal and telecommunications tycoon worth $15.8 billion US according to Forbes magazine, said in remarks carried by Russian television Tuesday that when he learned that Watson was selling the medal for charity he decided to purchase it and give it back to him.

Watson's 1962 Nobel prize for the discovery of the structure of DNA sold at Christie's in a New York auction for $4.7 million, a world auction record for any Nobel. The auction house said it was the first Nobel medal that was offered at auction by a living recipient.

Usmanov hailed Watson one of the greatest biologists in the history of mankind.