"I have joined our European Solidarity party! Today I wrote a statement and received a membership card," Poroshenko said.
He called on supporters to join the party. "Only we will ensure the movement of our country to the EU and NATO! We will protect Ukraine together!" he said.
The Bloc of Petro Poroshenko's Solidarity party was renamed European Solidarity on May 24.
At the same time, the updated party announced the holding of a congress on May 31 at which "the leaders of public organizations, volunteers, volunteer fighters, and young professionals" will be widely represented.