Aquaman himself was spotted filming in Santa Clarita with Zach Braff and Donald Faison Wednesday -- and if you check out the pics, you'll notice he's clearly bringing the excitement to this new T-Mobile ad with a huge smile on his face and jazz hands at the ready.

While Zach got up close and personal with JM -- basically singing right into his face -- DF got his own special moment with Momoa ... getting a crisp high-five from the 44-year-old. Hope your hand's doing OK, Donald!

As for the choreography ... Momoa's got it down. He starts by sashaying his way down the drive toward the street, singing into a fake microphone while he's at it before ripping open his button-down to reveal a black tank top.

The team seems to be dancing to a parody version of "Flashdance...What A Feeling" ... the song from the final scene in the film "Flashdance" -- Jason even leans back right at the end to pay homage to Jennifer Beals' iconic water scene in the film.

We know what you're all wondering ... it doesn't look like they drench Jason with a hose or anything at the end of the commercial -- but, hopefully, they already shot that part???

The crew seemed to appreciate the guys' efforts either way ... with the trio getting a rousing standing ovation at the end of the routine.

Speaking of routine ... these ads are becoming kind of a regular thing for Braff and Faison. They've done parodies of "Oh What A Beautiful Morning," "I Feel Pretty," and even roped the great John Travolta into one featuring a "Grease" parody.