Catherine was born to Malayali Syrian Nasrani Roman Catholic parents Frank Mario Alexander and Tresa Alexander in Dubai.[1] She said, "I don't speak fluent Malayalam, it's mostly English that we speak at home. I speak decent Hindi though and now I'm taking lessons in Telugu".[2] She did her Class 12 in Dubai and moved to Bengaluru for higher education. She studied for two years in St Joseph's College, Bengaluru.