Scots actress Laura Fraser plays crystal meth queen Lydia Rodarte-Quayle in Breaking Bad, the finale of which is expected to attract almost hysterical fan love when it screens in America tonight, and in Britain on Netflix on Monday.
Viewers who have watched the show over tortuous twists and turns throughout five series are desperate to find out how it ends ... and Fraser is one of the few who know.
"I am terrible with secrets," she told the Sunday Herald. "I am well known for revealing bits and pieces that my friends thought were sacred so I am terrified that I just blurt out, Tourette's-style, the end of the show.
"I am over in Glasgow while my husband films with Ken Loach in Ireland and I joked to my American friends that I was sequestering myself in Scotland so as not to give anything away.
"And then I get here and everyone's crazy about Breaking Bad. Even grannies have heard of it." Fraser only landed the part, central to the show's final fifth series, after the kind of disappointment that would shatter most actresses.
She was supposed to play Damien Lewis's wife in another hit series, Homeland ... but ended up losing that part.
"I had filmed the pilot episode with Damien Lewis,'' she said. ''Then I learned they had reshot it with someone else playing the part. I've since learned that that's a common thing in America, but I was more than a little bit heartbroken at the time.
"But if I hadn't lost that part then I would not have been in Breaking Bad, so I am so glad that happened. So glad."
Fraser, from Glasgow, is a small-screen veteran with parts in Small Faces and Lip Service, among others, and a slew of film hits under her belt - A Knight's Tale, Vanilla Sky and The Man In The Iron Mask, to name just a few.
The US show, about a high school chemistry teacher who is diagnosed with lung cancer and turns to drug production to raise money for his family, has gone from underground gem to watercooler hit.
Fraser, 38, now lives with her husband and daughter in New York but grew up in Glasgow and attended Hillhead High School before moving on to the then-Royal Scottish Academy of Music and Drama.
She stayed one year at the school. ''I was a little 19-year-old twit who thought I knew better than all the lecturers and was just awful. I'm so embarrassed to think of it."
LAURA ON LYDIA
LAURA Fraser found Lydia a brilliant character to play, but said: ''She is so tightly wound that I found myself physically exhausted at the end of each day from holding myself so tight. I had such a tight feeling in my chest.
"But the existing cast were just amazing and I knew I had to bring my best to this. Lydia was the most intriguing, brilliant character I had ever heard of
"It's going to be really hard to move on and leave Lydia behind me."
Praise for Fraser's take on Rodarte-Quayle has been glowing, not least from US critics. Alessandra Stanley, television critic with the New York Times, said Fraser had held her own among an "extraordinary" cast of actors.
Stanley said: "Nobody can predict if a performer is set to take off, but Laura Fraser has certainly shown viewers - and TV directors - what she can do. In an extraordinary cast of actors her performance as a prissy, nervous, lady-like executive who is also a ruthless drug dealer stands out.
"Lydia is a great character, and Fraser made it her own."
Fraser, who joined the show in its fifth season, had to work hard and fast to catch up with what was a tight, well-practised cast and crew.
Professor Maggie Kinloch, vice-principal of the Royal Conservatoire of Scotland and a huge fan of Breaking Bad, says the school wishes its former student well.
She said: "It's genius. The storylines are astonishing, the editing is amazing and the scripts are astounding.
"I am thrilled our former student is part of this incredible drama and I am very proud that the Royal Conservatoire of Scotland has been part of her actor training.
"Laura is a fine actor and I wish her phenomenal success in the future."