'Bachelor' Alums Peyton and Chris Lambton Expecting Baby No. 2

The Bachelor alums Peyton Lambton and Chris Lambton are growing their family by one, the couple announcing Tuesday that they are expecting their second child together, expected to arrive in December.

"Our team is expanding and we couldn't be more excited!! Baby Lambton will be here in December and Lyla James is ready for her promotion to big sister!" Lambton made the exciting announcement on Instagram, sharing a photo of herself and husband Chris with daughter Lyla James on his shoulders.

Chris — who competed on Ali Fedotowsky's season of The Bachelorette in 2010 — and Lambton, who competed on Andy Baldwin's season of The Bachelor in 2007, became engaged in June 2011 and married in 2012. In November 2016, they welcomed their first child together.

In a blog post shared shortly after announcing their first pregnancy, Lambton opened up about her struggles with "unexplained fertility" and the couple's difficulty becoming pregnant, telling readers that she had suffered a miscarriage and that little Lyla James was made possible with IVF treatments.

In another blog post shared shortly after announcing that they are expecting baby number two, Lambton explained that this pregnancy came as a "complete surprise" as she and Chris had "tried for years to get pregnant the old fashioned way and it didn't work," leading her to assume that they would need to go through another round of IVF treatment.

"God and the universe had other plans for us and we couldn't be more excited!! I feel a bit of empowerment that my body was able to do it's job. I'm happy that IVF exists and I am also happy to have a different experience this time around," Lambton wrote in the post.

"But the unknown is exhilarating and I am embracing this different experience and can't wait to meet this baby in December. We do not know the sex and we are going to wait to be surprised," she continued. "I have been sick as a dog, but I am finally coming around as we just passed the first trimester. The exhaustion is no joke, especially with a very active toddler running around. We can't wait to see Lyla James as a big sister. She is so nurturing and loves taking care of her baby dolls so I think and hope that will transfer into a real baby. Fingers crossed!"

The two are just the latest in a group of Bachelor alums who are expecting, with Bachelor Pad and The Bachelorette contestant Michael Staglianao and wife Emily having welcomed their second child in June.