'I love you. I miss you. I'll try to keep looking up': How Zelda's Little Prince was the most fitting Robin Williams tribute of all

The actor's surviving daughter celebrated her 25th birthday alongside her father just a week before he was found dead

This is the last picture Robin Williams posted on Instagram on his daughter Zelda's 25th birthday

"You - you alone will have the stars as no one else has them," Zelda Rae Williams posted. "In one of the stars I shall be living. In one of them I shall be laughing.

"And so it will be as if all the stars were laughing, when you look at the sky at night... You - only you - will have stars that can laugh."

It is apt that the tribute, made by Robin Williams’ beloved daughter, who celebrated her 25th birthday alongside her father just a week ago, was also the most fitting to his memory.

The quote was from Antonie De Saint-Exupery's book The Little Prince – a French novella written just after the outbreak of the Second World War. It was a turbulent and dark time for Saint-Exupery, as he himself struggled with poor health and depression amid tumultuous personal circumstances.

Yet through it, he went on to create the character of the young prince, who had fallen to Earth from an asteroid the size of a house. The story is one of loneliness, but also one of friendship, of deep loss but also of love. It is the story of an alien, essentially, who struggles to make sense of the world around him. And it is not unlike the story of Williams himself.

A family man in every sense of the word, it was the birth of his son, Zachary, in 1983, from his first marriage to Valerie Velardi that convinced him to seek help for drug and alcohol abuse – the substances he used to enhance how he viewed and interacted with the environment around him and followed a successful stand-up, TV and film career that showed no sign of slowing down. His friend and peer, John Belushi, had died of a drug overdose just hours after Williams snorted a line of cocaine with him at a hotel in Los Angeles.

"Cocaine for me was a place to hide," he told People magazine in 1988. "Most people get hyper on coke. It slowed me down. Sometimes it made me paranoid and impotent, but mostly it just made me withdrawn. And I was so crazy back then — working all day, partying most of the night — I needed an excuse not to talk. I needed quiet times and I used coke to get them."

Williams would go on to stay sober for 20 years. Not that he was perfect, in other areas of his life, however. In 1984, he had an affair with a cocktail waitress, Michelle Tish Carter, who would sue him in 1986 for not informing her that he had been infected with herpes. The case was settled out of court, but it led to the end of his marriage with Velardi in 1988.

He was a single man for less than a year, marrying Zachary’s nanny, Marsha Garces, in 1989 while she was several months pregnant with their first child, Zelda Rae Williams – named after the computer character from The Legend Of Zelda. They couple welcomed a second child, Cody Alan Williams, in 1991.

They remained married until 2008, when Garces filed for divorce citing irreconcilable differences.

"You know, I was shameful, and you do stuff that causes disgust, and that's hard to recover from," he told The Guardian during an interview in 2010.

"You can say, 'I forgive you' and all that stuff, but it's not the same as recovering from it. It's not coming back."

Five years before his second divorce, Williams and rekindled his relationship with a former demon. He had started drinking again on film location in Alaska in 2003 and in 204, his problem was further accentuated after his long-time friend, the actor Christopher Reeve, who he had known since they attended the Juilliard School together in New York, died of a heart attack.

Cody and Zelda Williams, Robin Williams and his ex-wife, Marsha Garces

"Because I felt alone and afraid," he continued, explaining why he went back to the bottle after 20 years of abstinence. "It was that thing of working so much, and going f**k, maybe that will help. And it was the worst thing in the world."

In the end, it was a family intervention that saw him hauled back into rehabilitation in 2007.

"It’s [addiction] — not caused by anything, it’s just there," Williams explained on Good Morning America after his 60-day stint in Oregon’s Hazelden Springbrook treatment centre.

"It waits. It lays in wait for the time when you think, 'It’s fine now, I’m OK.' Then, the next thing you know, it’s not OK. Then you realize, 'Where am I? I didn’t realise I was in Cleveland.'"

Zelda and Robin Williams, at the premiere of Old Dogs together in 2009

Sober again, and having recovered from a heart operation he had undergone in 2009, things were starting to look up. In 2011, he married his third wife, the graphic designer Susan Schneider.

"I kept thinking, 'She’s so beautiful', but I also had the feeling that I knew her," he said in an interview shortly after they wed.

"I said: 'Don’t I know you?' I know it sounds like a bad pick-up line. But it’s true."

Schneider, he said, had given him hope – and a new lease of life after his divorce from his wife of 19 years and numerous health problems that left him unable to fulfil the volume of work he had previously enjoyed.

But that hope, it seems, was fleeting. In July this year, after a long an arduous struggle to come to terms with depression, he was admitted to the Hazelden Addiction Treatment Center in Minnesota in order to "focus on his commitment" to overcome his addictions.

Robin Williams and his wife Susan Schneider at the premiere of "Old Dogs" in Los Angeles on 9 November 2009

"After working back-to-back projects, Robin is simply taking the opportunity to fine-tune and focus on his continued commitment, of which he remains extremely proud," his publicist, Mara Buxbaum, said at the time.

A month later, Williams was found dead in his home in North California after an apparent suicide.

"This morning, I lost my husband and my best friend, while the world lost one of its most beloved artists and beautiful human beings," Schneider said in a statement.

"I am utterly heartbroken."

Buxbaum later confirmed that Williams had recently been suffering from severe depression.

His last public message to the world was also a tribute ̶ to his daughter, Zelda.

"Quarter of a century old today but always my baby girl," he wrote, tweeting a vintage black-and-white family photograph of the pair from the early 90s. "Love you."

"I love you. I miss you. I'll try to keep looking up," she concluded her own.

Sadly, her Little Prince has fallen for the very last time.