It has already been ten days and many close friends left behind by ASTRO's Moonbin after his passing on April 19 continue to spend days in sorrow as they continue to remember the late idol.

Those who were closest to Moonbin are having it the hardest as they feel Moonbin's empty space that much more. One of Moonbin's closest friends, Seventeen's Seungkwan, is amongst those who continue to grieve the loss and he brought many fans to tears with his heartfelt letter to his best friend.

On April 28, Seungkwan posted on his Instagram a series of photos and video cherishing the memories with Moonbin along with a lengthy letter. 

Seungkwan wrote:

"You were a person who made the world look different. 

It's so hard to get along this well.

We walked together for hours without a destination.

Captured pretty sceneries on a camera.

Became lost in contemplation while looking at the night sky.

Became drunk and sang songs on the streets.

When I fell asleep drunk, you would always make sure to charge my phone before sleeping.

You would tell me to exercise even on the days pouring down rain,

So we went up to Namsan together, becoming drenched in the rain.

If we get hungry, we would order a late-night snack, eat it, and then sleep.

The next day, we would send pictures to each other, comparing who became more bloated.

When we would eat together,

you would happily watch me eat and say, 'Pops, you're eating so well,'

We would laugh endlessly at trivial things,

We would fight until our faces got red because of trivial words,

We tried not contacting each other, being hurt and out of pride.

But in the end, we would miss each other and say sorry to each other.

After reconciling, we would hang out having fun like never before.

We would play hard and then work hard as much.

You would be even good at doing that, so I would be proud of you.

You would monitor me more closely than anyone else,

and I respect you more than anyone else.

You were so polite and kind to everyone around me,

that everyone would praise you when you came up in conversation.

You would rejoice and be sad with me as if it happened to you.

We didn't shy away from saying 'I love you' to each other.

My friend Bin, who embraced me and comforted me until the end.

Saying you were a good person is far not enough to describe you.

You are what I can boast about in all my life.

This is enough for me to live proudly, worthy to be called your best friend, right?

If I want to see you, I can see you. If I want to hear you, I can hear you.

Because I believe you are watching over me in heaven.

You'll monitor me for this promotion, too, right? I'll reflect on your feedback, so please watch me. I'll make it through thinking that you're watching me.

It was an honor for me to become your friend.

And thank you so much for being my friend.

Thank you again for allowing me to learn and feel many things.

You can be anyone up there.

You can put down the sense of responsibility, pressure, and guilt

and wait for me while doing everything you like to your heart's content.

I'll live through everything.

So that these memories don't fade even a little,

I'll take care of your people

and reminisce together to our hearts' content.

For all the people who loved you,

I'll share these memories that I have far and wide.

Every time I do that, smile happily and watch.

If I have something to ask for, it's that you appear in my dreams.

You're my friend in our next life, no matter what.

I'll see you up there! I'll hug you tight as soon as I see you.

I love you so much. Bin, you worked hard."