The leader of the Ulster Unionist Party (UUP) brushed off accusations of performing a U-turn after announcing he would run in the General Election.
Sir Reg Empey will stand in South Antrim on May 6 despite his vociferous opposition to double-jobbing.
The Employment Minister and member of the Northern Ireland Assembly for East Belfast said he would have been the only party leader not contesting the Westminster election had he not stepped forward.
"The fact is that we want to give the electorate an opportunity to be a full part of a British General Election, demonstrating that we are part of a national election," he said.
William McCrea, the sitting MP, re-took the South Antrim seat for the Democratic Unionist Party (DUP) in 2005 with a majority of 3,448.
Other candidates declared for south Antrim in 2010 are Alan Lawther of Alliance and Mel Lucas of the TUV.
Sir Reg succeeded David Trimble as Ulster Unionist leader in June 2005.
The mayor of Antrim, Adrian Watson, had originally been selected as the party's candidate in South Antrim by the local Ulster Unionist association.
However, the Conservatives - who have an electoral pact with the Ulster Unionists - raised objections and he was rejected by a joint committee of the two parties.
DUP minister Arlene Foster said: "He very clearly said he was not running for Westminster, he said he wanted to concentrate on the Assembly and now all of a sudden he is running for Westminster and quite clearly he is doing this out of desperation, they could not get anyone else," she said.