strike while the iron's hot

In 1979, Jean Michel Basquiat, who at that time was pretty unknown in the art world, spotted Andy Warhol having lunch with Henry Geldzahler. He went up and introduced himself and offered to sell them some postcards he had painted. Geldzahler dismissed Basquiat, saying he was too young or something like that, but Warhol bought one of the postcards. 

Later, in 1982, after Basquiat had become a famous artist, they were more formally introduced and they had lunch together. After the lunch, Basquiat went home and painted a portrait of the two of them and delivered it to Warhol within a couple of hours after the lunch, with the paint still wet. Warhol confessed to Bruno Bischofberger, who was at the lunch with the two artists, that he was jealous because Basquiat worked so fast.