Yep, it's true!

Jessica Simpson is pregnant -- and she finally announced the news on Halloween with a cute, pun-tastic photo at on Monday.

Dressed as a mummy and holding her already-famous baby bump, Simpson, 31, writes, "It's true, I'm going to be a mummy!"

The baby-to-be will be the first for the singer and designer and her fiance Eric Johnson. Simpson has been the subject of baby speculation for months, thanks to an increasingly undeniable baby bump sported during recent outings in L.A., NYC and elsewhere.

Yale grad and former NFL pro Johnson, 32, proposed to Simpson back in November 2010 after about six months of dating.

"I met a wonderful man," Simpson tweeted of Johnson in September. "Damn, I'm lucky."

Added a pal close to the couple last December: "He really loves her. . . He's a low key guy. He's not into the glitz and materialism of Hollywood at all."

"Every day is a romantic day with him," Simpson said in December. "I'm very blessed."

Simpson's baby-to-be isn't the first grandchild for her parents Joe and Tina Simpson: That's Bronx, the 2-year-old son of Ashlee Simpson, Jessica's younger sister, and her ex Pete Wentz.

"I can't wait to have kids," the "Irresistible" singer gushed on The View last year.

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And, indeed, Simpson Tweeted of a prescient dream in March 2011. "Dreamt that I had a son named Tenacious D," she wrote. "That was a strange one."

The star's wedding plans, however, are still up in the air. "She can't figure out what kind of day she wants. Some days she wants a big wedding in Hawaii, then other days she wants something closer to home," a pal recently told new Us Weekly