Ariana Grande, Selena Gomez, Demi Moore and a bunch more celebs trekked up north to a historic city along the California coast for a film festival.

Ya gotta see the photos ... the "Wicked" star slipped into an extravagant, flowery pink dress to accept her Virtuoso Award at the 40th Santa Barbara International Film Festival.

Selena was all smiles at the SBIFF ... just like she was on a recent trip to Disneyland with her fiancé, Benny Blanco. She also picked up an award at the event.

SG skipped the Critics Choice Awards, but she looked stunning in Santa Barbara in a white dress.

Huge crowds turned out to get a glimpse of the Hollywood stars descending on SB ... and Demi dropped some knowledge after a screening of her film "The Substance," doing a Q&A with festival director Roger Durling.

Other celebs in town for the weekend included Jane Lynch, Sandra Oh, Monica Barbaro and Sebastian Stan ... just to name a few.