Former "Saved by the Bell" star Tiffani Thiessen has a baby on board! The 40-year-old actress announced on Instagram that she's pregnant with her second child.

"We are excited to announce the news that we are expecting," Thiessen captioned a photo of herself, her 4-year-old daughter Harper and husband Brady Smith. "Harper could not be more thrilled to have a sibling and a playmate."

Back in September, the "White Collar" actress told Sweden with Love magazine that she and her husband were trying to get pregnant with a second child. Thiessen also admitted that her daughter had been begging for a sibling.

"She puts more pressure on me than anyone!" Thiessen said, adding that her daughter asked her every morning "Is there a baby in your belly?"

"Every day, she begs me to have a baby. She can't wait to turn into a little mommy," Thiessen added. "She's ready!"

The actress also opened up about parenting telling the magazine that once her daughter turned four, she became a "full on kid."

"There are so many amazing things about a four-year-old. There's no baby left. She's full on kid. You can have complete conversations with her," she said. "She understands everything you say. We can enjoy a lot of the same things. But it's also an interesting age, because there's a lot of pull back and forth. One minute she wants to be a big kid and the next she wants her mommy. That can be challenging. But I enjoy her company so much, no matter what stage she is in."

Thiessen also added that her daughter, who is currently very-much into princess dresses at the moment, is a "very high spirited girl."

"She doesn't stop until she's completely worn out," she told Sweden with Love. "She knows what she wants, and that can be challenging at times. But I don't ever want to quash her spirit or change the fact that she's a strong-willed little kid."