Rumer Willis and boyfriend Derek Thomas are officially parents.

The 34-year-old recently gave birth to her baby girl, Louetta, and she's now opening up about the magical experience. On Mother's Day, May 14, Willis took to Instagram to share a glimpse into her water birth, writing, "To my girl, my most precious girl Lou, I have waited and dreamed of you my whole life."

She continued, "You are more than I could have ever imagined. You have changed my life in the most profound way. It is the privilege and honor of my life to be your Mother and I will do everything and anything for you always. I hope you never stop wanting to sleep next to me or take baths with me."

The touching upload featured the actress smiling as she was submerged in water with Lou resting on her mother's tummy. Another sweet image showed the Masked Singer alum giving birth in the water as her sisters, Tallulah, and Scout, held her hand.

"I can’t wait to see who you are, although I feel like I have known you my whole life," she continued in the caption. "One of the first things i said after you were born was 'oh my girl, I missed you' I didn’t even realize I had said it til @buuski told me later but it’s true. I feel like i have always known you and you me. You are the most beautiful creature I have ever met. I still wake up every morning and can’t believe you are mine."

As she wrote on, Willis thanked her daughter "for choosing me to be your mama," adding, "Thank you for trusting me to guide you through your life. Every moment and contraction and every bit of the pain of birth was worth it and I would do it a thousand times over if it means getting to spend one sec with you."

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Willis went on to thank her boyfriend for being there for her throughout the process, writing, "@derekrichardthomas my partner in crime in this uncharted journey into parenthood thank you for giving me the gift of this beautiful soul and for catching our girl as she came into the world and for holding such beautiful space for me as I brought her into the world. She is so lucky to have you as her papa and loves you so much. We are so grateful for you and love you so much."

Of course, Willis' sisters also got a special shout out, as she noted, "To my sisters, my best friends, my partners in crime to have you there to share in the moment that I was able to bring my girl in the world is a moment I will never forget. You have watched and supported me on the journey and know what it meant to bring another precious girl into our lineage."

She closed out the caption by sending love to her newborn, writing, "I love you my girl you are the greatest joy and gift of my life. Love your mama."