David Tennant voices a lightsaber professor in the Star Wars series (Picture: Disney/Getty)

David Tennant surprised fans by appearing in a small role in the Star Wars series Ahsoka.

The Doctor Who actor, 52, voices Huyang the droid professor who taught young Jedis how to build lightsabers in The Mandalorian spin-off, which follows Ahsoka (Rosario Dawson) investigate an emerging threat to a vulnerable galaxy.