Quentin Tarantino has admitted he's ''steering away'' from his 'Star Trek' movie.

The 'Pulp Fiction' director previously pitched an R-rated script for a new instalment in the rebooted franchise to producer J.J. Abrams.

The 56-year-old filmmaker has always vowed that he will make 10 movies and then retire and his proposed 'Star Trek' film would reach that number, but he has now cast doubt on whether it will ever happen, as he admitted he's ''not had an official conversation'' about it yet.

He told Consequence of Sound: ''I think I'm steering away from 'Star Trek', but I haven't had an official conversation with those guys yet.

''In a strange way, it seems like this movie, ['Once Upon a Time in Hollywood'], would be my last.

''So, I've kind of taken the pressure off myself to make that last big voilà kind of statement.''

Tarantino added that he now sees his last big screen outing as ''being a little smaller''.

He said: ''If the idea that all the films are a boxcar and it's all one train, they're all telling one story.

''Well, [Once Upon a Time] is the climax, so I can actually see now my 10th movie probably being a little smaller.''

Although he admitted he could change his mind, he says a low-key flick is more ''appealing'' to him at present.

He continued: ''Look, I might come up with a really big idea.

''But right now, the idea of a smaller audience almost all the way around is appealing to me.''

Tarantino previously confessed if he commits to directing 'Star Trek' then it will be his final film.

He said: ''I guess I do have a loophole, [if] the idea was to throw a loophole into it.

''Which would be [to go], 'Uh, I guess 'Star Trek' doesn't count.

''I can do 'Star Trek' ... but naturally I would end on an original. ''But the idea of doing 10 isn't to come up with a loophole.

''I actually think if I was going to do 'Star Trek' I should commit to it. It's my last movie.

''There should be nothing left-handed about it.

''I don't know if I'm going to do that, but that might happen.''

Several original 'Star Trek' actors are all for Tarantino's movie.

George Takei - who starred in the 1960s television series 'Star Trek: The Original Series' as Hikaru Sulu - said he'd be willing to play a part depending on the script.

And William Shatner - who played James T. Kirk - said he'd be up for it, too, if it was set many years later.