Danielle Fishel marked her 40th birthday with a stellar announcement.

The "Boy Meets World" alum announced on Wednesday that she is expecting her second child, a son, with her husband, Jensen Karp.

The actress appeared happy and healthy in a photo in which she cradles her bump in a floral dress and whtie sneakers.

"F O R T Y! I've never been more excited or hopeful for the next decade of my life. I had a beautiful childhood, teenage years I still dream about, my 20's were insane (and mostly miserable) and my 30's brought me lows and highs but eventually I leveled out to a place of security," Fishel shared in her caption.

'BOY MEETS WORLD' STAR DANIELLE FISHEL TACKLES 'MOM GUILT' IN EMOTIONAL ESSAY

LOS ANGELES, CA - MARCH 06:  Actress Danielle Fishel attends the private screening for "Boiling Pot" on March 6, 2014 in Los Angeles, California.  (Photo by Ben Horton/WireImage) (Ben Horton/WireImage via Getty Images)

She goes on to say that, at 40, she has "security in who I am, what I believe, and with whom I want to spend precious time."

"I couldn't be more grateful to enter my 40's with my amazing husband and son, excitedly expecting the arrival of baby boy #2. My birthday wish is for all of you to tell someone how much you love them and walk through today with more patience than you normally might," she concluded her post.

Fishel and Karp got married in November 2018. They already share one son, Adler Lawrence, who will turn 2 in June.

In 2019, the star penned an emotional essay for "Good Morning America" that covered her emotional toil during her first childbirth. Adler was born with fluid in his lungs and thus remained in the neonatal intensive care unit at Children’s Hospital Los Angeles for several weeks. Fishel's husband stood by their side for every step of the harrowing journey.

In the essay, Fishel noted that the concept of "mom guilt" was something that she didn't expect to experience.

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"I had heard of ‘mom guilt.’ It was right up there with other types of guilt I heard about growing up, like 'Catholic guilt' or 'Jewish guilt.' I heard it was the awful feeling you’re never doing what you’re supposed to be doing, or not doing enough of what you should be doing, or not doing what you should be doing well enough," Fishel candidly wrote.

"As a childless woman looking at all mothers I knew, I could only see how incredible they were. Their kids were happy, well-loved, fed and clothed. Some of them went back to work and others didn’t. Those decisions were not made selfishly, but based on privilege and what was best for their children and their families."

Upon returning to work, Fishel experienced further guilt in terms of potentially abandoning Adler. "Does he remember me? Does he think I abandoned him? Am I hurting my son by desiring a career outside the home? Am I selfish?" Fishel wondered.

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Fishel ultimately concluded with support for hard-working mothers out there. "When you see a mom feeding her baby formula, or breast milk in a bottle, or directly from her breast, or through a feeding tube (I have done all of these in Adler’s 15 weeks of life), or you see a mom dragging a screaming toddler through Target, or you see a mom calling home from work, or you get a text from a stay-at-home mom who is ready to pull her hair out, know that there is a story there."