Prince William Grows Beard, Positive Reviews Online

Prince William's looking rough and rugged these days ... changing up his iconic look with a thick beard on his jaw -- and, people are loving it.

The Prince of Wales stepped out at the Royal Air Force (RAF) College in Cranwell Thursday ... clad in his sleek military uniform and ready to present an award to a graduate cadet during the Sovereign's Parade.

Check out the pics ... the beard's pretty prominent here -- brown and slightly graying whiskers, he's 42 after all, covering his royal chin as he chatted with servicemen and walked the grounds.

It's a different look for the future King of England ... who many are used to seeing clean-shaven, bald head gleaming in the sun.

BTW, not the first time Will has been seen with the beard in recent days -- he's been growing it out for a while -- but, this is the thickest we've seen it so far.

If you're wondering about the internet reaction ... X is abuzz with people complimenting the prince on his new look. Many say they weren't sure on day 1 or 2 of the stubble -- but add it's quickly growing on them, and him, obviously.