Labour MP Owen Smith has decided not to stand at the upcoming general election.
He said it was because of "political and personal reasons".
On Twitter, Mr Smith said he has written to Labour leader Jeremy Corbyn tonight to inform him of the decision.
He also said, "It has been a great honour and a privilege to serve the people of the Pontypridd Constituency."
Mr Smith has been the Pontypridd MP since 2010.