The children of late actor Christopher Reeve have added their tribute to their dad's close friend and college roommate Robin Williams, thanking the tragic funnyman for his "simple, steadfast friendship" over the years.

The pair struck up a friendship back in the 1970s, while attending New York's prestigious Julliard School, where the aspiring actors became roommates.

They remained close after college and made a vow to one another, promising that the first person to make it big in Hollywood would take care of the other, and Williams was there for his old pal in 1995, when he was left paralysed following a horse riding accident.

The Mrs. Doubtfire comedian reportedly helped to pay for Reeve's medical treatment and lifted the quadriplegic's spirits as he prepared to undergo life-saving surgery by bursting into the operating room, pretending to be an eccentric Russian surgeon ready to perform a rectal exam on him.

Williams, 63, died from a suspected suicide on Monday (11Aug14), 10 years after Reeve suffered a fatal heart attack in 2004, and now the Superman star's family has honoured the funnyman's memory.

In a statement issued to, they write: "For Robin, our dad was 'Brother Reeve'. Robin was a light in our family for as long as we can remember. He and Dad made each other laugh, and they stood by each other to the end. Our hearts ache for his family."

Williams, who dedicated his Cecil B. Demille Award at the 2005 Golden Globes to his late friend, was also a key supporter of the Christopher & Dana Reeve Foundation, a charity set up by the Reeve family following the death of Christopher's wife, Dana, in 2006. The organisation aims to raise funds to find treatments and cures for paralysis caused by spinal cord injury.

Charity officials added their words of condolence late on Monday, in a message that reads: "While the world knew Robin Williams as an Oscar-winning actor, we knew a different side to the man whose smile was as big as his heart.

"While our hearts ache with the loss of our friend, it is unlikely Robin would want us to mourn his passing with silence, but to celebrate his life through laughter.

"Together, let's remember Robin for the man who made the world laugh."