The four-time MP, who won the 2009 elections with a margin of 11,790 votes, is a former Chemistry Professor of Sacred Heart's college here and has served as state Tourism, Excise and Fisheries minister between 2001-04.
Thomas has already completed the first round of campaigning and booth conventions are presently on.
An upbeat Thomas says the message to the electorate is that only Congress and UPA can give a stable government.
On taking Fernandez, a former Gujarat cadre IAS officer, Thomas said, "We are good family friends. There is no foe in politics. We only are fighting on two fronts".
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Fernandez, Secretary of former President Pratibha Patil, will have to sweat it out in the polls as he was taking on a veteran. Both Thomas and Fernandez are from the predominant Latin Catholic community.
However, he has clarified that during the Godhra riots, he was in Kerala as Coir Board chairman.
BJP has fielded State General Secretary, A N Radhkrishnan, who had tested electoral waters in the constituency in 2009.
The Aam Admi Party (AAP) has put up journalist Anita Pratap.
"Common facilities like toilets and bathrooms are lacking in various places", she said criticising the Congress.
The candidates are eyeing the one lakh odd new voters in the constituency.
A Congress bastion, Thomas has represented the constituency in 1984, 1989, 1991 and 2009.
In the bypoll in 1997, Sebastian Paul was elected as CPI(M) independent candidate from the constituency while in 1998 and 1999 polls George Eden of Congress emerged victorious.
In the 2003 bypoll and 2004 general elections, Sebastian Paul was elected from the constituency.