United Kingdom, July 23 -- Robin Williams' son has paid tribute to the late actor's "weirdness and extraordinary capacity to love" in honour of his 75th birthday.

The Mrs. Doubtfire star - who took his own life in August 2014 - would have celebrated the milestone birthday on 21 July, and in honour of the occasion, Zak Williams urged fans to "do something kind" for someone in memory of his dad.

He wrote on his social media pages: "Happy 75th Dad! Today I'm remembering your weirdness and your extraordinary capacity to love.

"I remember those wrinkles in the corners of your eyes, the kind you get from a lifetime of smiling. I remember your unending need to see this world free of human and animal suffering.

"For those out there who'd like...