Dear Bestie Mcbest,

You've got this.

I know you're worried. I know you're scared. All that lies before you right now is one big, amazing and sublimely terrifying mystery. You're wondering what kind of mother you're going to be, if you'll be a good one. What I know (I know, I know for sure) is that You've. Got. This.

I've seen you with my own children. Where you question yourself, like we all do, wondering if you'll be a good mother, I have no doubt. With my children you are kind, patient, loving, fun. You'll be all these things, and so much more, with your own. You have the biggest heart of anyone I've ever known. Your baby, is the luckiest one.

I want to tell you that when your baby arrives, you can ask for my help. I know you think that because I have three young children of my own, you can't. But I'm telling you that you can. If I can help, I will. I want to. Because; I'm invested.

I want to tell you that when your baby arrives, you can ask for my advice.

But you don't have to take it.

I won't begrudge you finding your own way, I'll celebrate it. Because; I'm invested.

I want to tell you to take every piece of advice that you are given, well meaning or otherwise, with a grain of salt. And if anyone makes you dinner, add salt to that too, because people notoriously scrimp on seasoning when they cook for others!

I want to tell you that I will love your baby. You know how you've loved mine? Each and every one of them, even though we were both quite sure that neither of us even liked toddlers before I had them? Well, just like you've loved mine, I will love yours. Because; I'm invested.

I want you to know that if I could be, I'd be walking the halls of the hospital while you're in labour, pacing, worried. Excited. Drinking disgusting coffee from a styrofoam cup. Wanting to be the first person that you and your husband introduce to your little human when it's born. I want to do that. But I won't. Cos that would just be weird.

And, more importantly, I draw the line at hospital coffee. A girl is allowed to have standards.

I want you to know that no matter how you do it, I'll be proud of you. If you have an epidural. If you don't. If your baby sleeps well. If it doesn't. If you never complain about being exhausted. If you complain every single day. If you implement a routine. If you take each day as it comes and fly by the seat of your pants. I'll be proud of you no matter how you do it, no matter how well you cope, no matter how many times you feel like you're failing. Because you won't fail. Not in any way. And I'll be proud. Because; I'm invested.

I want to tell you that I am your family. I've never had a sister but I know that if I did have one, I'd still like you better. I am in this for the long haul; my kids, your kids. Our kids. A family. Because; I'm invested.

"I want to tell you that I will love your baby." (Image: Getty Images)

I want to tell you that if, given time, you feel like you need to move interstate to be with your actual family, I will understand. I'll be half a heart without you, but I will understand. And I'll always be here. Because; I'm invested.

I want to tell you that we will always be us, despite our children. Us. Hilarious, ridiculous, fabulous, idiots. Clueless quoting, boy-band-loving dreamers with secret shared Pinterest boards that no one need know about. Old enough to know better but having too much fun to care. We can still just be you and me. We always will be. There may be more to us now, but we are still us, too. Us two.

So much about life is about to change for you. But one thing will remain the same. Us.

You're my best friend. You're having a baby!!!

You've got this.

Liv Williams is a Mum and blogger at Eenie Meenie Miney Mum.