In a recent Instagram post, Kristen, who lives in the US, wrote: "Well, I'm Pregnant. And, yes. It's Sam's. She then went on to explain how she came to be pregnant, revealing how the couple went through IVF after discovering Sam had cancer. Kristen was heavily pregnant with their son Jack in 2011 when they discovered Sam was ill.
"In order to have more biological children after cancer treatment, Sam and I had to go through IVF," she writes.
She goes on to explain that their daughter, Alice, now two, was the product of one of four frozen embryos and the couple wanted to have another baby. Writes Kristen: "We tried again this past summer with another, but I lost it very early. Two weeks after that, Sam relapsed and three weeks after that, he was gone."
Kristen says the couple talked about having another baby even if Sam died.
"Even in the ICU during his final hours, I knew what I was going to do," writes Kristen. "After he was gone I laid next to him for a long time."
Kristen tells how earlier this year with both her mum and Sam's mum with her, she had the final two embryos implanted.
"There were a lot of tears and so much love in that room. I found out a few weeks later that I was carrying one strong baby. And that's OK. The way I see it, I get one and Sam gets one. Of course, it's bittersweet. And yes, a bit unconventional. But it was our decision and what I consider to be one of life's most beautiful blessings."