Though she now has four children with actor Alec Baldwin, Hilaria Baldwin, host of "Mom Brain," was once a new presence in the life of Ireland, Alec's daughter from his marriage to Kim Basinger.

In an intimate Instagram caption from Thursday, April 18, Hilaria opened up about what it was like being a new step-mom and how the pair have grown to love each other as much as any flesh-and-blood relatives.

Hilaria wrote about how being a stepmom is a different experience than one she'd ever had before:

"I rarely address being a stepmom, but it is part of our family. I always want to deal with it with such care...so often you hear horror stories about evil stepparents and I wanted to make sure I did right by the family I was stepping into when I married Alec."

"I love my stepdaughter as much as I love my biological children and I become a mommy lioness when I see comments that insinuate otherwise."

She was very clear with Alec: if Ireland did not approve, the relationship would go no further.

"Having a stepchild is a delicate matter. Especially one who is grown. I think my relationship with her has been so successful because I never tried to step in as her mommy."

"She has a good mother, who I have tremendous respect for...and I put myself in Kim's shoes: if my children ever had a stepmother, I'd want her to let me be number one."

"When I met Ireland, I said to Alec: if she is not ok with our relationship, I cannot go further. Family is first and she needed to be ok with me."

Since then, the pair have gotten along famously!

"We have never had a fight or a bad moment. Nor have I with her mother. Ireland and I love each other and she knows that I am here for her...and I know that she is here for me."

"I am inspired by her, look up to her (not just height wise 😂)...she gave her father away at our wedding, is the best big sister anyone could ask for...and I give her space. I don't ever expect her to be anyone other than herself."

Hilaria knew her job wasn't to be Ireland's new mom, but a new friend and role-model who would always be there for her.

"As someone who loves her, my job was not to step in and take over...but rather respect what had been for the first 15 years of her life and then become a part of that, in a way that works for everyone."

"So yes, sometimes my language about my biological children does not include her. Because I did not birth her and I never want to disrespect the fact that she has a wonderful mother. But this will never take away from how much I love her, need her in my life, and think that she is one of the best things that has ever happened to me."

"Please don't look for trouble where there is none. Love you @irelandbasingerbaldwin ...ps after writing this and using the word "step" so many times, I think I know why it is called a 'stepparent' now."

Social media users connected with her heartfelt statement:

hilariabaldwin/Instagram

hilariabaldwin/Instagram

hilariabaldwin/Instagram

Baldwin has developed a reputation for her candid honesty on social media recently, sharing the story of her recent miscarriage with her fans to normalize the fairly common occurrence:

Fans certainly appreciate Hilaria's bravery:

Thanks for being so open, Hilaria, you're inspiring us all!