UNESCO Director-General Audrey Azoulay says she is proud of the United States' intention to rejoin the UN cultural and scientific agency in July.
Azoulay revealed during a hastily arranged meeting at UNESCO headquarters in Paris on Monday that she received a letter from Washington.
The US also stated its intention in the letter to settle past dues, according to UNESCO officials.
Azoulay said, "This is a great day for UNESCO, for multilateralism", and that "This is the result of our collective action. You can be proud of it, we can all be proud of it."
In 2017, the administration of then President Donald Trump announced the US was withdrawing from UNESCO, citing what he called the anti-Israeli stance of the body. Washington officially pulled out the following year.
Observers say Washington made the decision to show that President Joe Biden's administration is highly committed to the values of international cooperation.
Besides UNESCO, the Biden administration decided to rejoin both the 2015 Paris Agreement on climate change and the UN Human Rights Commission, reversing the policies of the Trump administration.