The series aired its final episode just two weeks ago and Hopkins, in his letter, writes how he was hooked to the story of Walter White, a lung cancer-stricken chemistry teacher, who turns to producing and selling methamphetamine.
In his letter, the 'Hannibal' star said Cranston's acting as White was the best he had ever seen, said the Hollywood Reporter.
"A total of two weeks (addictive) viewing. I have never watched anything like it. Brilliant! Your performance as Walter White was the best acting I have seen -- ever.
Hopkins also goes on to praise the rest of the cast as well, and asks Cranston to "pass on my admiration to everyone."
"Everyone gave master classes of performance." He also praises the Vince Gilligan-created show's overall arc and storytelling.
"From what started as a black comedy, descended into a labyrinth of blood, destruction and hell. It was like a great Jacobean, Shakespearian (sic) or Greek Tragedy."
The 'Breaking Bad' series finale aired on September 29, drawing a record 10.3 million viewers.
