Experts are still finding out more and more about American graffiti artist Jean-Michel Basquiat, 24 years after his life was cut short by a heroin overdose. Like so many other stars, his life ended at the age of 27, not that long after he'd built a reputation for himself.

His creations are greatly coveted by collectors and a self-portrait of Basquiat sold for an impressive £2.1m last summer.

Now, with a major work by the artist going under the hammer, Sotheby's has made a very useful discovery.

First, let's look at the artwork. The extremely startling work Orange Sports Figure was created using acrylic, oil stick and spray paint on canvas in 1982. Although the figure's identity is undisclosed, some have suggested it is of Basquiat's childhood hero, baseball player Hank Aaron.

This was one of a number of highly celebrated works of sport stars which Basquiat created in his lifetime, and features his trademark three-point crown motif. 1982 was a great year for the artist, who had finally established himself and was creating some of his greatest works as a neo-Expressionist studio artist.

Jean-Michel Basquiat's Orange Sports Figure

It was already listed at £3m-4m in Sotheby's contemporary art auction which takes place tonight (February 15) in London. But a chance discovery has raised the excitement to another level.

The viewing of the painting under ultraviolet light revealed the presence of a signature in invisible ink. This is likely to power-up the bidding substantially.

Basquiat may have led a short life, but it was an action-packed one. He appeared in a video for band Blondie and rubbed shoulders with Andy Warhol.

Collectors who wish they'd had a chance to get close to Andy Warhol will be pleased to know that a polo neck jumper which the artist famously wore is available for sale from our stock right now.