Adam Sandler makes every effort to prepare "SNL"

Adam Sandler "went crazy" to make sure this week's "SNL" episode was "the most memorable of all times," a source told Page Six.

The comedian – who returns for the first time to the show as a host since 1995 – stays in the studio until 4 o'clock in the morning.

"He basically sleeps there," said a source.

Sandler said in his agenda "Late Night With Seth Meyers": "I must tell you that it knocked me out."

We hear that he has even brought back some of the great writers of the series.