Iranian Foreign Minister Mohammad Javad Zarif will attend international talks on the Syrian crisis being held in Vienna this week, a government spokeswoman has said.
It will be the first time that Iran – an ally of Syrian President Bashar al-Assad – has attended such talks.
Earlier, the US said an invitation to the meeting had been extended to Iran.
The talks will include foreign ministers from the US, Russia, Saudi Arabia and Turkey.
The main round of talks is expected to take place on Friday, but diplomats say some preparatory meetings could happen on this evening.
“We have reviewed the invitation, and it was decided that the foreign minister would attend the talks,” Iranian foreign ministry spokeswoman Marzieh Afkham said.
Egypt and Iraq also confirmed they had accepted invitations to the meeting.
BBC diplomatic correspondent James Robbins says that while the US is certainly not welcoming Iran to the Syria talks, it will now tolerate Tehran’s involvement.
Iran’s Fars news agency said Mr Zarif had discussed participation in the Vienna talks with Russian Foreign Minister Sergei Lavrov by phone on Tuesday.
Kremlin spokesman Dmitry Peskov later told reporters that Russia wanted a “widening of the dialogue” on Syria.
Iran is believed to have spent billions of dollars over the past four years propping up President Assad’s government, providing military advisers and subsidising weapons.