Shaggy Says All Jamaicans Should Support Bob Marley Biopic

Bob Marley's biopic is the biggest thing sizzling at the box office despite mixed reviews ... but that's no excuse to miss it if you're a real Jamaican ... as far as Shaggy's concerned.

TMZ Hip Hop caught up with rapper/singer at the Island Music Conference in Kingston this past weekend -- and he tells us straight up ... it's completely "un-Jamaican" for any native NOT to support the flick.

Divisive words for sure ... but Shaggy's not sipping on hypocrisy here -- he's been a staunch supporter of the film himself and even recently attended the 'One Love' premiere in L.A. alongside Brad Pitt, Stevie Wonder and several members of the Marley family.

The film has been accused of skimming through the late-reggae legend's life too quickly -- but Shaggy defended the film, as well as lead star Kingsley Ben-Adir's vocal performance.

Kingsley's British, so he had to be coached to learn his Jamaican accent, which opened him up to more criticism. Of course, all the singing done on-camera ain't him ... it's Bob.

Anyway, Shaggy gives us an honest review of his own -- he admits Kingsley's dialect wasn't spot-on but still thinks the guy gave a believable performance considering he's not actually Jamaican ... so, KBA gets his seal of approval here.

The film's success could potentially make the Marley clan billionaires ... something Shaggy is counting on if people heed his advice.