2003 Manassinakkare Malayalam Winner, Asianet Award for Best Female New Face of the Year
2004 Vismayathumbathu Malayalam Natturajavu Malayalam 2005 Ayya Tamil Chandramukhi Tamil Thaskara Veeran Malayalam Rappakal Malayalam Ghajini Tamil Sivakasi Tamil Special appearance in song Kodambakkam Area
2006 Kalvanin Kadhali Tamil Lakshmi Telugu Boss Telugu Vallavan Tamil Thalaimagan Tamil E Tamil
2007 Yogi Telugu Dubai Seenu Telugu Sivaji: The Boss Tamil Special appearance in song Balleilakka Tulasi Telugu Billa Tamil Winner, Vijay Award for Favourite Heroine
2008 Yaaradi Nee MohiniTamil Winner, Vijay Award for Favourite Heroine Nominated, Filmfare Best Tamil Actress Award Kuselan Tamil Simultaneously made in Telugu as Kathanayakudu Sathyam Tamil Aegan Tamil Twenty:20 Malayalam Special appearance in song He Dil Deewana
2009 Villu Tamil Anjaneyulu Telugu Aadhavan Tamil
2010 Adurs Telugu Bodyguard Malayalam Goa Tamil Guest appearance Boss Engira Bhaskaran Tamil Filming Simha Telugu Filming Electra Malayalam Filming Super(hand symbol)Kannada Filming
Diana was spotted when she was still in college by director Satyan Anthikkad, who casted her opposite Jayaram in Manassinakkare. Later, she co-starred alongside Mohanlal in Natturajavu and in Fazil's Vismayathumbathu. She was also cast with Mammootty in Thaskaraveeran (Dubbed into Tamil as Yuvaraj) and Raapakal. After this she went into Tamil and Kannada. She has also starred in several Tamil, Telugu movies. She was cast opposite Sarath Kumar in Ayya and with Rajnikanth in Chandramukhi. Her later films Vallavan (Tamil) and Yogi (Telugu) flopped except for Tamil film Ghajini, where she played a secondary female character. She regained her star billing in Kollywood acting opposite Ajith Kumar in the remake of Billa. Yaaradi Nee Mohini released in 2008 was a huge hit and received seven nominations at the 56th Filmfare Awards (South). It was one of the highest grossing Tamil films of the year. Her next release Kuselan opposite Rajnikanth, Sathyam opposite Vishal, Aegan opposite Ajith Kumar and Villu opposite Vijay were all unsuccessful. Her latest successful appearance was in Aadhavan with Surya Sivakumar which released on 16 October 2009 and was successful.
She was educated in various parts of India (Bangalore, Mumbai and Kerala),as her father was an Indian Air Force official. She is a Syriac Orthodox Christian (Jacobite) by birth. She attended Balikamadom High School, Thiruvalla for +2,then attended Marthoma College in Thiruvalla for her Bachelor's degree in English Literature. She is a native of Tiruvalla, Pathanamthitta district.