Pamela Anderson thinks the late Hugh Hefner was ''lonely'' when he passed away.

The Playboy founder was 91 when he passed away in September this year after suffering from cardiac arrest, respiratory failure, sepsis and an E. coli infection, and despite being married to his third wife Crystal Harris at the time of his death, Pamela, who was close friends with the entrepreneur, believes he felt alone.

She said: ''[He was] lonely in the end. He was surrounded by women but he was lonely.''

Pamela, 50, also recalled a time when she had grown worried about the ''circle'' of women he had surrounded himself with, and made sure to let the late star know that there would always be ladies who loved him.

She added: ''I remember him getting teary-eyed one day because I said, 'You know there are women that love you,' because he was in this circle that got a little crazy.''

The blonde beauty - who has Brandon, 21, and Dylan, 19, with her ex-husband Tommy Lee - was told about Hugh's passing by one of her sons, who informed her via text, and the 'Baywatch' star says the news was ''devastating''.

Speaking to The Times magazine: ''It was devastating, the end of an era. But he was not very well. Physically, he was in a lot of pain, so it's OK.''

Previously, Pamela had shared a lengthy post on social media about everything the Playboy magazine founder taught her over the years.

She wrote: ''Goodbye #Hef Mr Hefner

I have so many thoughts, I have no brain n right now to edit

I am me because of you / You taught me everything important about freedom and respect.

''Outside of my family / You were the most important person in my life.

''You gave me my life ... People tell me all the time

''That I was your favorite ... I'm in such deep shock. But you were old, your back hurt you so much. Last time I saw you / You were using a walker. You didn't want me to see.

''You couldn't hear. You had a piece of paper in your pocket you showed me - with my name Pamela with a heart around it... (sic)''