'Duck Dynasty' Star Alan Robertson -- My Dad Is a Prophet and a Martyr!

"Duck Dynasty" star Alan Robertson is defending his dad Phil Robertson's controversial views on homosexuality ... and even thinks his pops is "a 21st Century prophet."

As we told you ... the elder Robertson doubled down last month on the homophobic remarks he made to GQ magazine ... with a new fiery sermon on Easter Sunday.

Alan -- who's also a preacher -- spoke up for his father at a religious event earlier this month in D.C. ... and likened Phil to John the Baptist. Alan said Phil "has the heart and the mindset of a prophet … long hair, long beard, naturally camouflaged, he ate off the land and he pointed people to Christ."