Its still not quite the same as Japan. Porn is still largely seen as something done out of desperation in the west, a route of last resort, as this very thread can attest. You work in porn in the west, and you pretty much can't work in any other job, and your social status is basically one half notch above prostitute. Very few pornstars have enjoyed crossover success really. Sibel Kikelli (who you pointed out as Tyrion's girlfriend) and Sasha Grey are probably the two biggest examples, and even Sasha Grey isn't that big of a name, while Sibel is more well known in Europe, which is more open about sex than the U.S. in general.
In Japan, porn is seen as a legitimate career path and AV idols are well known mainstream media personalities and household names even during their porn careers. And, as I said, many AV idols start out in the entertainment industry garnering mainstream success before going into porn, so you have plenty of people making the transition the other way around, something which is practically unheard of in the west outside of the extremely washed up. In Japan, many music artists and other media personalities will transition to porn for a while then just return back to doing what they were doing before at a later date.