LONDON (AP) — A British music scholar says he has identified a previously unknown portrait of Wolfgang Amadeus Mozart that could be worth millions.

The 19-by-14-inch oil painting shows the profile of a man in a bright red jacket. Cliff Eisen said Friday that it is only the fourth known authentic portrait of Mozart from his time when the composer was at his professional height in Vienna, Austria.

"This is arguably the most important Mozart portrait to be discovered since the composer's death in 1791," Eisen said in a statement that appeared on the Web site of King's College London, where he teaches music.

King's College said the portrait was probably painted by Joseph Hickel, who was a painter at Austria's imperial court. Hickel gave the portrait to Mozart in return for the composition of a serenade for a member of Hickel's family, the college said.

Eisen said he was able to authenticate the portrait by comparing it against auction records, archival documents and a letter written by composer to his father in 1782.