Lance Bass says the only way a potential *NSYNC biopic is ever getting off the ground is if he's a producer ... and he's already got an idea for how to tell the band's story.

We got Lance at LAX on a rainy Friday afternoon, and our photog asked him about a much-talked-about biopic that hasn't quite gotten off the ground. Getty

Lance says it may well happen down the line, but he explains why there are some major hurdles to clear.

If it ever comes to fruition, though, he's not sure sure who should play him on the big screen ... joking with us that he needs to bone up on the younger generation of actors before he can confidently make a pick. Getty

We broke the story ... the biopic stalled because the guys just weren't sold on the pitch or the producer behind it. Justin Timbe

See Full Page