NBA stars LeBron James and Kobe Bryant have praised Barcelona forward Lionel Messi, calling him the best footballer in the world.The United States basketball stars are in Europe for the London Olympic Games, and were full of superlatives when asked to describe the Argentina international."Messi is the best player in the world. And, if he is not already, he will be the best player of all time,” James said in an interview with EFE."Messi is the best ... the best!” Bryant agreed.“Once I had the opportunity to see a Barcelona training session and I really enjoyed it.”Messi has won the Ballon d’Or award three times in a row, and is widely expected to be a front-runner again for 2012.