Here's a portrait of Alexander the Great as Zeus Ammon (check out the ram's horns, symbolizing divinity) on a silver tetradrachm of Lysimachus, 297–281 bc, thought to be a copy of a portrait by Lysippus; in the British Museum. Diameter 30 mm. Click on the
Encyclopedia Britannica for more.

According to
Wikipedia, "Lysippus' sculpture, which is opposite to his often vigorous portrayal, especially in coinage of the time, is thought to be the most faithful depiction of Alexander."
Courtesy of the trustees of the British Museum; photograph, J.R. Freeman & Co. Ltd.