Rudy Giuliani announced that Republican presidential candidate Donald Trump isnt a birther anymore.

I confirm that, the former mayor of New York City told Chris Matthews in a testy segment on MSNBC s Hardball on Thursday. And Donald Trump now confirms that.

Trump has never confirmed that.

I dont talk about it , Trump told NBCs Ali Vitali on Monday.

For a time, Trump was the most prominent backer of the birther movement, a conspiracy theory that claimed President Barack Obama wasnt born in the United States. Trump has never publicly backed away from those claims despite the release of both short-form and long-form birth certificates proving Obama was born in Hawaii.

After several minutes of back-and-forth on the issue, Giuliani began laughing.

I dont think this is funny, Matthews scolded. I think when you accuse the president of the United States of being someone who snuck in the country and assumed an identity, because thats what Trump has been doing for years now.

Wait, a second. Wait, wait, wait, Giuliani shot back, then proceeded to blame Democratic presidential candidate Hillary Clinton for the issue another conspiracy theory that has also been debunked .

Her campaign raised it originally, Giuliani insisted.

No, Matthews said. Youre wrong.

See the full exchange above.

Editors note: Donald Trump regularly incites political violence and is a serial liar , rampant xenophobe , racist , misogynist and birther who has repeatedly pledged to ban all Muslims 1.6 billion members of an entire religion from entering the U.S.