The following story contains MAJOR SPOILERS for the third season of "Doctor Who."

Two weeks ago, legendary theater actor Sir Derek Jacobi stepped into the fantastical world of Doctor Who for a one-episode role devised to bring back a classic iconic villain. That villain was, of course, the worst kept secret of the series, with reports leaking out as early as the fall that The Master would be returning.

One thing that fans didnt expect was seeing two completely different takes on the character as Jacobi regenerates into a younger more vibrant character portrayed by John Simm, an actor who Jacobi himself describes as a marvelous up-and-coming young actor.

Speaking with the official Doctor Who magazine, Jacobi admitted how excited he was to take on the role of The Master and also how people reacted when he broke the news.

Im a fan, but not a fanatic, he told the magazine. I have a friend who I didnt know was a fanatic, and when I told him: well, first of all I said I was going to be a villain in Doctor Who.He whooped! I mean, just went hysterical. When I said that Id be playing a character that becomes The Master, he thought that it was the pinnacle of my career! It can never get better for me than this.

"I was told that what I was going into was tremendously important to millions of people, and actually that contributed greatly to my approach, knowing that I was entering a kind of legendary world, and that I had a responsibility to that world. So no pressure then.

Although news of his performance may have excited millions of the show's followers, Jacobi admitted he has no plans on watching the episode because he is his own biggest critic.

Its never what you think you did, he told the magazine. Its never how you think you looked. You think Oh God, if Id thought I looked like that:!And, oh, the voice never sounds the way that you expected it to, or hoped it would. Total disappointment. No, no, I cant be objective, and so I cant enjoy it.

The thing that Jacobi tried to keep in mind is that none of it is real, and that he can put his own unique spin of the character in a way that none of the previous actors who have played The Master have done.

Its an imaginary world - an unreal world. Thats why we all act like children, he said. I mean, some actors more than others - yes, Im thinking of John Barrowman. But were kids, and its essential that we are.

Your own personality is the biggest stamp that you put on it, Jacobi said. Like Hamlet. There are as many Hamlets as there are actors, really.

Simm, who also spoke with the magazine and who took on the role of The Master in the last few minutes of Utopia largely agreed with Jacobis outlook on taking on the character. However, he felt the need to take a look back at his predecessors who made up the original classic series and at one point even thought about bringing a familiar look to the character.

I actually did say to Russell, Shall I have a goatee? The goatee beard? he said. With the best intentions in the world, Im thinking, Ill do something really different with it, but I know what will end up happening: Ill turn up with a big floppy hat and a cane, rubbing my hands together, laughing manically," Simm said. "But Russell said No, no, hes modern. Hes a new Master. Once I got that in my head, I realized that, you know, this is not Sylvester McCoy's Doctor Who.This is the David Tennant era. This is not Roger Delgado. This is me.

Although he wasnt worried about matching the previous incarnations of The Master, Simm said he did want to know one thing: How the last Master perished. Unfortunately, he didnt quite realize how much of a painful experience that would be.

I didnt concern myself with not measuring up, Simm mused. I just wanted to know how Eric Roberts died [in the 1996 telemovie], thats all, so I had to sit through that movie to find out. The whole movie. I did it in two parts, though. With a bottle of wine.

The only worry Simm said he had about stepping into The Masters shoes was keeping the character grounded in reality and not becoming so wildly outrageous that he would not be believed.

Its a tough one, because you kind of think, If I cant go over the top on this, when can I go over the top? he said. The thing is, hes the prime minister at first, so I cant be really, ridiculously over the top, he continued. Ive got to be kind of believable. They cast me for a reason: Im not known for going wildly over the top; Im kind of the opposite, so I couldnt start being all bwhahahaha!I thought, Well, I dont want to be pantomime.

Whereas Jacobi instantly accepted the role to fulfill one of his lifes ambitions (aside from working on Doctor Who, he also has a desire to appear in Coronation Street), Simm did it primarily because his son would never forgive him if he said no.

Its one of those opportunities, though, to impress your son in a massive way, and that was too good to turn down, Simm said. Also, Julie [Gardner] was trying to find something for me to do in it. She kept sort of saying, What about this?And I kept saying, Look, Im not being painted blue.And then Julie and Russell [T. Davies] came down to Manchester when I was filming Life on Mars,met me in a bar after a night shot, and said, What about The Master?As soon as they said that, I was like, Youre kidding? Oh yeah!I got really excited about it, but I just had to sit on the news. I wanted to tell people Im going to be the Master!But its a secret isnt it?

The third season finale of "Doctor Who" airs Saturday night on BBC One in the United Kingdom, and the season itself moves to SciFi Channel in the United States in July.