Clint Eastwood's Daughter I'm Getting an Annulment From Jonah Hill's Bro

11/25/2013 12:40 AM PST

Francesca Eastwood's marriage to Jonah Hill's brother will end faster than you can say Britney Spears and Jason Alexander ... because she's getting the week-long marriage annulled ... TMZ has learned.

Sources close to the regretful couple tell us ... the notion of getting hitched was fueled by alcohol -- and lots of it.  Francesca and Jordan Feldstein ended up in a cheesy Vegas wedding chapel and took their vows amidst faux greatness -- an Elvis impersonator.

Francesca had immediate regrets.  We shot her the day after the nuptials and she wasn't wearing a wedding ring.

We shot Clint Eastwood a few weeks ago asking for marriage advice and he told our photog to not rush into anything.

Guess Francesca should have listened.