PayPal Founder Elon Musk -- Actress Wife Talulah Riley Files for Divorce

Millionaire PayPal founder Elon Musk's wife has filed for divorce ... TMZ has learned.

The British "Pride and Prejudice" actress -- named Talulah Riley -- filed the papers on January 17th, citing "irreconcilable differences" ... one day before Musk publicly announced the couple's split on Twitter.

In a telephone interview with Forbes on the 18th, Musk -- worth a reported $680 million -- made it sound as though he was the driving force behind the divorce, claiming, "I still love her, but I’m not in love with her. And I can’t really give her what she wants.”

The Forbes headline reads, "Elon Musk to Divorce Wife" -- but clearly, Talulah beat him to the punch. So far, Elon has NOT filed divorce documents.

It's unclear who truly wished to end the relationship, or whether it was a mutual decision.