Credit: Noel Vasquez/Getty Images

More outrageous news from Tila Tequila: she's pregnant!

After proclaiming her engagement to heiress Casey Johnson Dec. 9, the MTV reality star tweeted her latest "big announcement" Sunday:

"I am going to become a SURROGATE MOTHER for my brother and his Wife!!...That is my xmas present to them," she writes.  "I'm pregnant!!!"

Earlier, she teased that she was giving her brother a present that would "CHANGE HIS LIFE AND MINE FOREVER!!!! ITS HUGE!"

Tila (real name: Tila Ngyuen), 27 has not yet provided additional details about the due date of the child or how she reached the momentous decision.

She is also apparently being generous with her parents this year -- she notes on the microblogging site that she's "going to surprise my Mom & Dad & Buy them a new house in Vietnam where they can retire & B happy."

The star recently showed off her engagement ring from supposed fiancee Johnson. She said it was a "17-carat diamond ring from my baby...My baby takes care of me. Beat that J.Lo! Beat that Khloe and Lamar!"

All the happy news follows darker headlines from Tila: she had recently alleged that her ex-boyfriend, San Diego Chargers quarterback Shawne Merriman, choked and restrained her at his home; her claims were dropped in September due to insignificant evidence.