Sundaramurti Nayanar was a great devotee of Lord Siva. He is one of the four Saiva Acharyas. Lord Siva of Tiruvennainallur appeared before Sundaramurti in the form of an aged Brahmin on the eve of his marriage.
https://d3t3ozftmdmh3i.cloudfront.net/production/podcast_uploaded_episode400/5254746/5254746-1635156338974-f3932ea81ffb8.jpg