The head of Oxfam Cymru has been named as the Labour candidate for the Cardiff South and Penarth by-election.
Stephen Doughty will seek to succeed Labour MP Alun Michael, who is standing down in a bid to become south Wales' first elected police commissioner.
Mr Doughty said he was "immensely proud" to have been picked.
The Liberal Democrats and Plaid Cymru have already chosen their candidates for the by-election, the date of which is yet to be set.
Dr Bablin Molik, a researcher at Cardiff University, will stand for the Lib Dems, while the Plaid Cymru candidate is Luke Nicholas, a researcher for the party's assembly group.
The Conservatives are yet to announce their candidate.
Labour won the seat with a majority of more than 4,700 over the Conservatives at the 2010 general election.