The team of Harry Potter, including the lead cast members Danielle Radcliffe and Emma Watson, has paid heart-touching homage to actor Alan Rickman, most famously known for his role of strict professor Severus Snape in the fantasy film series.

Rickman has died following a battle with cancer. He was 69.

Radcliffe played the young braveheart Harry Potter, who for the most part of the series found Snape against him, only to find in the end that he was his well-wisher in disguise.

Remembering the brilliance of Rickman on and off screen, in a long post, Radcliffe tweeted, "Alan Rickman is undoubtedly one of the greatest actors I will ever work with."

"He is also, one of the loyalest and most supportive people I’ve ever met in the film industry. He was so encouraging of me both on set and in the years post-Potter."

"I’m pretty sure he came and saw everything I ever did on stage both in London and New York. He didn’t have to do that.

I know other people who’ve been friends with him for much much longer than I have and they all say "if you call Alan, it doesn’t matter where in the world he is or how busy he is with what he’s doing, he’ll get back to you within a day."

The 26-year-old star said he liked that the veteran treated him like a colleague not a child on the Harry Potter set.

"As an actor he was one of the first of the adults on Potter to treat me like a peer rather than a child. Working with him at such a formative age was incredibly important and I will carry the lessons he taught me for the rest of my life and career. Film sets and theatre stages are all far poorer for the loss of this great actor and man," he wrote.

Watson, who played intelligent, sensible Hermoine Granger, was not far behind to express her sadness.

"I’m very sad to hear about Alan today. I feel so lucky to have worked and spent time with such a special man and actor. I’ll really miss our conversations. RIP Alan. We love you."

Actor Matthew Lewis, who was the cute and usually timid Neville Longbottom, wrote, "I was at Leavesden Studios today when I heard the news. As I walked through the canteen I thought of Alan queuing up for his lunch with us mere mortals.

"I recalled the trailer in which he offered me some of the greatest advice I ever received about this mad profession we shared. He inspired my career more than he ever knew and I’ll miss him."

Posting a picture of Rickman as Snape, actress Bonnie Wright, who played Harry’s love interest, wrote on Instagram, "Alan. The energy shifted every time you walked onto set. You were an inspiration to us all. RIP"