625 Nathan Road.
Thanks to Raymond Lo for the history of this location:
Previously on this site was the cinema variously known as Portland Theatre / Victory Theatre / New East Asia Theatre.
1953: The site was redeveloped, and the new Ritz Theatre opened on 20th March, 1953. It closed on 1st June, 1972.
1970s: The site was redeveloped yet again and the Ritz Building, an office building, was built on this site.