Robin Thicke Performs for Lavish Wedding at Base of Pyramids in Egypt

It might not be clear how pyramids were built, but if they're in ruins we certainly know why ... 'cause Robin Thicke's performance in Egypt may have brought them down!

The singer-songwriter played a wedding gig at the base of the architectural marvels Friday night at the Wedding of Ankur Jain and Erika Hammond -- a couple moguls who pulled out all the stops for their big night.

One of the many exciting surprises ... Thicke pulled up to croon a few tunes -- including iconic love song "Just the Two of Us" and man, the guy sounds fantastic.

Check out the clip -- Thicke's got the crowd up and moving, and the happy couple dancing together onstage ... no blurred lines between them that's for sure!

BTW ... Thicke's performance wasn't the night's only entertainment -- 'cause a DJ named Gryffin also performed, and his set was accompanied with fireworks over the pyramids.

If you don't know ... Ankur and Erika are pretty dang big in the business world. Ankur started travel rewards company Bilt Rewards and Erika founded KNOCKOUT at Equinox -- so, they got money to blow on a lavish ceremony.

Robin's a close friend of Ankur's, so he agreed to perform at the wedding -- the first of its kind at the base of the pyramids we're told ... which we're told cost north of $1 million.

The happy couple received 150 guests including "Shark Tank" star Kevin O’Leary, Lance Bass and his husband Michael, Miami Mayor Francis Suarez, "Million Dollar Listing New York" star Ryan Serhant and his wife Emilia ... among more famous faces.

Unclear how much RT got paid -- if at all -- but, we imagine he cut the groom a friends and family discount at the very least ... so, presumably no $6 million bag like Rihanna reportedly got when she played a wedding last month.