Paris Hilton and Nicole Richie Film 'Simple Life' Reboot in New Video

Paris Hilton and Nicole Richie are back together, posing for paparazzi like it's 2005 ... and, TMZ has an exclusive look at them filming for "The Simple Life" reboot.

The dynamic duo was photographed outside the Saban Theater in Beverly Hills earlier this week ... posing for cameras on the sidewalk, black gowns on and blonde hair beauty pageant ready.

Check out the clips ... Paris helps Nicole adjust her outfit and there's lots of smiling and giggling between the two -- until a crew member comes over to tell the ladies they gotta move things along.

She gives them a few notes of direction, and PH and NR appear really receptive ... listening intently before walking off to get the shot for the show.

Looks like they filmed their entrance into their "Paris & Nicole The Encore" show too ... coming out of the building in full view of the audience inside before bursting back into rapturous applause.

Of course, the longtime pals have their fans going nuts for the new series ... filming the show at a Sonic Drive-Through earlier this month -- and drawing lots of eyes to the reboot.

We broke the story ... the two stars already had the show greenlit by May, and production sources promise it's not a copy-and-paste remake of 'TSL' ... it's going to be a reboot in every sense of the word.