Katie Holmes has celebrated James Van Der Beek's "journey of a hero"

Katie shared a hand-written message on Instagram, in which she wrote: "James, thank you. To share space with your imagination is sacred - breathing the same air in the land of make-believe and trusting that each other's hearts are safe in their expression.

"These are some of the memories, along with laughter, conversations about life, James Taylor songs - adventures of a unique youth ...

"Bravery. Compassion. Selflessness. Strength. An appreciation for life and the action taken to live life with the integrity that life is art - creating a beautiful marriage, six loving children - the journey of a hero.

"I mourn this loss with a heart holding the reality of his absence and deep gratitude for his imprint on it."

The Logan Lucky actress - who has 19-year-old daughter Suri with ex-husband Tom Cruise - vowed to be there to support James' widow Kimberly and their six children.

She added: "To Kimberly and the children, we are here for you always. And will always be there to shower you with love and compassion."

Katie admitted James' death is a "lot to process".

She wrote: "I formed some words with a heavy heart. This is a lot to process. I am so grateful to have shared in a piece of James' journey. He is beloved. Kimberly, we love you and will be here always for you and your beautiful children. [heart emoji]."

Katie's post came in the wake of other tributes from the cast of Dawson's Creek.

Busy Philipps - who played Audrey Liddell on the show - wrote on Instagram alongside photos of herself and James over the years: "My heart is deeply hurting for all of us today...every person who knew James and loved him, anyone who loved his work or had the pleasure of meeting him, all of his dear friends and community that surrounded him as he battled this illness, especially his parents and brother and sister.

"But I am profoundly heartbroken for his incredible wife Kimberly and their six magical children. There is a go fund me for them to help out and i'll put the link in my stories. James Van Der Beek was one in a billion and he will be forever missed and i don't know what else to say. i am just so so sad. He was my friend and i loved him and i'm so grateful for our friendship all these years.[heart emoji].(sic)"

Kerr Smith, who played Jack McPhee on the show, paid tribute to his "brother".

He wrote on Instagram: "I'm so grateful for being able to call James a brother. I'll miss him deeply. Rest easy."

James' Dawson's Creek screen mom, Mary-Margaret Humes, admitted her co-star's passing had left her "at a loss for words".

She wrote on Instagram: "Rarely am I at a loss for words ... today would be the exception.

"James, my gracious warrior, you fought a hard battle against all odds with such quiet strength and dignity. I will always love and admire you for that.

"Our last conversations ... merely a few days ago ... are forever sitting softly in my heart for safe keeping.

"To our extended Dawson's Creek family of friends, please be respectful of our silences at the moment as Beautiful Kimberly and family have asked for peaceful privacy for now.(sic)"