The couple has been together for five years.
To share the news, Hudson posted an adorable shot of her and Fujikawa smiling as they lean in for a kiss. The actress rests her newly ring-adorned finger on her fiancé's chest in the pic, as he snapped the photo.
"Let's go!" Hudson captioned the pic, adding wedding-themed emojis.
The couple began dating in 2016, though they've known each other for more than a decade. The pair welcomed their daughter, Rani, in 2018. Hudson is also mom to Ryder, 17, and Bingham, 10, from previous relationships.
While speaking to ET in 2019, Hudson said she didn't plan to marry Fujikawa "anytime soon," before adding, "I love the man."
A month later, Hudson gushed about her then-beau in an interview with Women's Health.
"I've got the best man," she said. "It's the first time I feel like I have a real teammate in this. We're able to pick up where the other one has to leave off. If I have to go to a dinner meeting, he can be home."
"His number one priority is family," she continued. "And when we have our disputes, I feel the thing that allows us to get through them is having the same ultimate goal, and that includes being in each other's life. It just feels so nice."