Jean-Michel Basquiat wasn’t one of those painters who drew attention posthumously, he lived it. Rising to stardom in the 1980’s, the New York-based impressionist was known for his abstract, crazed style of paintings often covered in doodles and graffiti. Although much of his work is covered in words, very few of them had his full signature… until now. The prestigious Sotheby auction house in London recently found Basquiat’s signature in an invisible pen on “Orange Sports Figure,” currently up for bid. The artwork, worth between $4.7 and $6.3 million, will go on sale on Wednesday.

"The signature just popped out," said Cheyenne Westphal, the head of contemporary art at Sotheby's Europe on Tuesday. She says the staff was initially "surprised, astonished and puzzled” at the pen mark suspected to be the kind used for marking banknotes. Gerard Basquiat, the Haitian father of the late painter and authenticator of all his work, has not publicly commented but there’s little doubt that this is anything but an original piece. Sotheby experts are excited that they may have opened the door to other Basquiat pieces being inspected for ultraviolet marks. The auction house has not changed the sale price since the discovery.

What are the chances that there are more Basquiat paintings out there with invisible signatures?

Read it at The Grio.