Prince William, Prince Harry Set to Stagger Diana Legacy Event Appearances

Prince Harry and Prince William are both set to attend a memorial event for their late mother, Princess Diana -- but as for them kickin' it in the same room ... forget it.

The brothers are gearing up for a rare joint appearance at the Diana Legacy Award event at the Science Museum in London Thursday ... but Harry's not hopping on a plane to be there, 'cause he'll be beaming in virtually from his home base here in California.

So, here's how it's gonna go down, per reports ... William will kick things off, doing his speech and handing out 20 awards at the ceremony -- held to reflect Princess Diana's belief that young folks can totally shake things up and make a difference in the world.

Will's gonna be riding solo to the event -- as his wife Kate Middleton continues to be noticeably MIA -- and once he wraps up, Harry's gonna zap into the room afterward.

Reports say Harry is going to wait until William completely leaves the stage before coming on himself. Safe to say, this is not a good sign of where their relationship is ... it's still icy.

The siblings have been locked in a feud for years now, which intensified after Harry and Meghan Markle's bombshell interview with Oprah and their Netflix special. It all came to a head with the release of Harry's memoir, where he laid bare the deets of their rift.

Remember, Harry said William got physical with him back in 2019 ... claiming he grabbed him by the collar, ripped off his necklace, and straight-up knocked him to the ground -- this after he supposedly called Meghan "difficult," "rude," and "abrasive."