Hugh Hefner celebrated his 88th birthday by hosting his traditional 'Casablanca' movie night.

The Playboy founder has held the same event for more than 20 years and decided he's not yet bored of marking his big day with family at friends at the Playboy Mansion in Los Angeles.

Hugh, who celebrated his birthday on April 2, shared a number of photographs on Twitter with his 1.43 million followers.

He also posted: ''Tonight we start my weekend birthday celebration with the screening of my all time favourite film 'Casablanca' with family and friends.''

He shared one snap of him cosying up to wife Crystal, 27, at the Beverly Hills bash, accompanied by the caption: ''Here's looking at you, kid'', a quote from the 1942 movie.

Hugh also shared an image of male guests wearing white formal jackets and a group of women posing in the foyer.

In honour of his birthday, Hugh also looked back at his life in 'CBS This Morning's 'Note to Self Wednesday'.

Addressing his 16-year-old self, he said: ''After launching Playboy magazine in 1953 ... you'll come out from behind the desk and become Mr. Playboy, the embodiment of the magazine you've created. You'll even inspire those around you to reinvent themselves.

''The girl next door will become an international sex symbol through the pages of Playboy. Librarians, lawyers and even your own secretary will use Playboy as a tool to re-imagine themselves.''

He added: ''Millions of readers will aspire to live the Playboy lifestyle and you will challenge them to question what they believe about sex and sexuality, about personal freedom and civil rights.''