Neil Hamilton, UKIP leader in the Welsh Assembly, has been selected as a candidate for his party to fight the general election.
Mr Hamilton announced he would be standing in Carmarthen East and Dinefwr, currently held by Jonathan Edwards for Plaid Cymru.
The former Conservative MP, who was raised in Ammanford, said he was "delighted" to fight the seat for UKIP.
He currently represents the Mid and West Wales region in the assembly.
Jonathan Edwards is standing for re-election for Plaid Cymru, while Labour has selected David Darkin as its candidate.
Spokesmen for the Conservatives and the Liberal Democrats said their parties were planning to choose their candidates next week.
A full list of candidates will be available after nominations close on 11 May.
Following his selection, Mr Hamilton said: "I am delighted to receive the unanimous support of my own branch and to be confirmed as their candidate to fight the seat for UKIP, as I did for the assembly elections last May.
"I was raised and educated in Ammanford and am proud to represent the area in the assembly, as part of my region of Mid and West Wales."
Mr Hamilton, the Conservative MP for Tatton from 1983 to 1997, was a minister in John Major's government but lost his seat to independent challenger Martin Bell in the 1997 election.