Odo on Deep Space 9 was surprised to see others of his species. Is that who you’re thinking of?
Rene Auberjonois, Odo Chief of Security Seasons 1-7 Deep Space 9, Changeling Constable (unofficial)
Constable Odo is the station’s incorruptible chief of security. He is a Changeling, capable of assuming any shape he wishes. He was found and raised by the Bajorans. Odo yearns to find his own people, but when he finally does, he is less than pleased to discover that they rule the Gamma Quadrant with an iron fist.