Ben Stiller breathed new life into the Oscars on Sunday with his hilarious Joaquin Phoenix impersonation.

We were thinking: Amazing! Creative! Funny! How does he come up with this stuff?!

Well Page Six has the answer. Stiller had "a meltdown" at rehearsal on Saturday "because he was unhappy with the script and decided he could do better," said an insider.

"Ben refused to tell them what he planned until he arrived at the Kodak Theatre, and then he did that Joaquin Phoenix bit."

However Stiller loses creativity points because director Frank Coraci did the SAME THING the night before at the Independent Spirit Awards.

Stiller did it better, but he wasn't the first. Click here to watch take one of the Joaquin impersonation.