Billy Crudup says acting is not for the faint of heart, is teeming with rejection and can sometimes include hatred.

“Almost immediately in acting school, there’s only 20 of you there, somebody gets the great part,” he told Page Six at the premiere of “Jay Kelly” at the New York Film Festival on Monday night.

The actor, 57, then went on to list all the ways rejection rears its ugly head.

“Not getting an agent,” he explained. “Not getting an audition, getting the audition, not getting the part, getting the part but being cut out of the movie, getting the part, being in the movie, nobody seeing the movie.”

Crudup then added that an actor can be in the movie, and people see it, but they “hate you.”

“You can be nominated for an Academy Award and lose it; there’s just no end to it,” he concluded.

In his new movie “Jay Kelly,” the Tony winner plays a longtime friend of a famous movie star (George Clooney), who hasn’t achieved the same success as his pal.

Thankfully, Crudup said he has never experienced this scenario.

“I’ve been very lucky with the friends that I have,” the “Almost Famous” star shared, “and the friendships that I’ve formed with my colleagues. It hasn’t been that kind of antagonism or resentment.”

However, the “Morning Show” star noted that he could easily see how “someone who would get some early success in their career, can lighten the load of their friendships and cut bait from some people who were important to them.”

Crudup cautioned that it’s a career choice only for people who “really want to do it.”

Other celebs at the starry premiere, held at Film at Lincoln Center, included George Clooney, Laura Dern, Josh Hamilton, Riley Keough and Patrick Wilson.

“Jay Kelly” will receive a limited release on Nov. 14, before it moves to Netflix on Dec. 5.