Fans have now flocked to his Instagram with a new sense of heartbreak and intrigue.
TheTop Gunstar was heard speaking with his cancer treatment-affected voice.
I am heartbroken that you are no longer with us, Val.
I pray you are resting in peace, one said.
Thank you so much for your art!
You will be deeply, deeply missed!
I lost my father in December last year to Pneumonia, wrote another.
He, too, had a trachy after throat cancer.
He lived every day after that surgery to the fullest.
As Im sure you did, too.
Forever, my Batman, rest in peace, one said.
Kilmer also posted a couple of paintings as his last two posts on Instagram.
His portrayal of the masked vigilante of Gotham made him one of director Joel Schumachers most favorite Batman.
Everything was different about this job than Id experienced before, he previously toldET.
I have behaved poorly.
I have behaved bravely.
I have behaved bizarrely to some, he said in the documentary.
And I am blessed.
Image credits:Hulu
Numerous stars took to social media to share condolences over the actors passing.
See ya, pal.
Im going to miss you, Josh Brolin wrote alongside a picture of him beside Kilmer.
You were a smart, challenging, brave, uber-creative firecracker.
Theres not a lot left of those, the actor added.
Check out the results: