Johnny Depp has recalled the hell of seeing his young daughter hospitalized with kidney failure, branding it the worst time of his life.

Lily-Rose Depp, now 16, was just seven years old when she contracted E.coli poisoning while her father was shooting a movie in London, and she was taken to the city's Great Ormond Street Hospital when her kidneys began to shut down.

She spent nine days at the specialist children's unit receiving treatment before she recovered, and Johnny later showed his appreciation to staff by donating $1.6 million to the hospital.

He has also made several visits to Great Ormond Street since, to entertain and read to young patients while dressed as his Pirates of the Caribbean character Captain Jack Sparrow.

Now the revered actor has spoken out about the family's nightmare nine days in 2007, revealing his admiration for the staff at the hospital spurred him on to make even more visits to children's wards.

Johnny tells U.K. talk show host Graham Norton, "For me it's a gift. They give me the gift. When my daughter was ill in Great Ormond Street it was the darkest period of my life. I'd always done these visits but after that experience the visits became more and more important. The kids are so courageous but to be able to bring a smile or a giggle to the parents means everything in the world to me."

Lily-Rose is Johnny's daughter by his ex, singer Vanessa Paradis. He is now married to actress Amber Heard.