Kate Spade began to distance herself from her friends before her tragic death.

The 55-year-old fashion designer was found dead in her apartment in New York earlier this week in an apparent suicide and, although her passing came as a shock to many, her friends had started to realise something wasn't quite right beforehand.

A source told 'Entertainment Tonight': ''Kate definitely seemed to distance herself recently and her family was worried about her.

''She ventured out less and less and some friends began to wonder what was wrong. People who were used to hanging out socially with her started to worry about her because she was nowhere to be seen.

''Kate's suicide has been extremely heartbreaking and has left some friends confused because she kept a happy persona in public for so long. But those that knew her well, knew she suffered for years with depression.''

Although those close to her had known about her battle with depression, Kate tried desperately to hide it from the public for fear of it ruining her fashion brand.

The insider explained: ''She truly cared about her brand and didn't want the public to know of her pain. Kate's suicide has made some friends question what they could have done to change the horrific outcome. She definitely hid the truth of her intense suffering from so many friends, and in turn they had no idea she needed help.''

Friends and family are now trying to rally around Kate's 13-year-old daughter Frances, whom she had with her husband Andy Spade, following her death.

The source said: ''Right now we are all looking for answers and are so worried for her young daughter.

''Kate loved her daughter so much, but clearly couldn't endure the pain any longer.''

Kate - who was living separately from her husband at the time of her death - left a suicide note and reportedly mentioned how it wasn't Frances' ''fault.''