In her suicide note addressed directly to her 13-year-old daughter, according to gossip website TMZ, she wrote: "Bea - I have always loved you. This is not your fault. Ask Daddy!"
Paying tribute, her brother-in-law David Spade has now taken to Instagram to share a loving photograph of them together with his 1.2million followers.
The Hollywood star wrote: "Fuzzy picture but I love it. Kate and I during Christmas family photos. We had so much fun that day. She was so sharp and quick on her feet."
He added: "She could make me laugh so hard. I still can't believe it. It's a rough world out there people, try to hang on."
In this morning's Daily Mail, it's being claimed that Kate suffered from manic depression for years but refused treatment. The paper also claims that she was "obsessed" with the actor Robin Williams' death.
"She was surrounded by YES people, for far too long, therefore she did not receive the proper care for what I believed to be (and tried numerous times to get her help for) bipolar disorder... stemming from her immense celebrity," Kate's sister Saffo told the DailyMail.com this morning.

“I adore pretty things and witty words.” Rest In Peace #KateSpade, you’ve made generations of women feel more confident and supplied so many of us with bags that make us happy. pic.twitter.com/88u0jAUCpP

— Little Miss Type A (@LilMissTypeA) June 5, 2018

Famous designer, #KateSpade, dead at 55 from apparent suicide.

To the person feeling lonely, tired, sad, confused, or hopeless - you are not alone. We’re all working through this messy thing called life - together. Please keep going. https://t.co/Xri5crdeZ4

— Blake Odgers (@Blake_Odgers) June 5, 2018