PRETTY WOMAN” Julia Roberts has been looking pretty plump lately, sparking whispers that the mom of three may be pregnant again!

But The ENQUIRER has learned that Julia, 46, turned to food to deal with the stress of caring for her elderly mom, Betty Lou Motes, who was hospitalized three times for an excruciating back problem.

“Julia’s not pregnant,” confirmed a source. “But she’s sick about her mom and she’s been trying to eat her worries away.

“The discs in Betty’s back have degenerated, and it got so bad she had to have an artificial disc implanted. She had two surgeries recently. The first one didn’t work out. She was still in a lot of pain and had to be taken to the emergency room.”

Doctors discovered that the implant had shifted, which meant Betty needed to undergo another operation. Meanwhile, she was put in a back brace and needed to take pain medication. Julia was so concerned that she moved Betty into her Malibu home temporarily to keep a close eye on her.

But it hasn’t been easy – especially with awards season getting under way. Julia, who earned a Golden Globe nomination for Best Supporting Actress for her role in “August: Osage County,” has been promoting the movie along with taking care of her mom. “It’s all taken an emotional and physical toll on her,” said the source.

Betty has since moved back into her nearby Pacific Palisades home, where Julia’s sister Lisa is now caring for her.

As for Julia, the source says she’s “frantically trying to take the weight off as fast as she can.”