Tori Spelling's due date revealed by mom Candy Spelling

Tori Spelling's once-estranged mother, Candy Spelling, couldn't hold her excitement -- or her tongue -- about the upcoming birth of her daughter's fourth child.

"She's expecting on my birthday, Sept. 20," Candy tells In Touch. "But it's going to be a cesarean, so she's going to have it earlier."

Tori and husband, Dean McDermott, have three other children: Liam, 5, Stella, 4, and Hattie, 8 months. The couple conceived just six weeks after the birth of little Hattie.

"It was a little soon. Her body didn't get back in shape, so I think it's a lot for her," Candy says.

Ouch -- think the mom and daughter reunion will be short-lived?