Seriously, how the hell is she still that attractive? This is almost supernatural. I know plastic surgery is part of it, but she clearly hasn’t gone overboard and wrecked her face. So what else is going on with her to explain this? Is it the Asian ancestry? Bathing in the blood of virgins?
Kim Cattrall could give Tilly a run for her money. She’s over 50 – closer to 55 than 50, I believe:
What assurance do we have that those photos were taken of them at their current age? I’m dubious. (“How’d you do, Dubious? I’m Doctor Krankheit.”)
Kim Catrall is stunningly young looking, but Tilly (and this probably is due to the Asian genes) still has that roundness on the edge of the jaw that usually signifies a just-post-adolescent.
Kim Catrall, I look at and think, “Wow, she looks GREAT!” Jennifer Tilly I look at and think, “No way, that birth year can’t be right!” and I spend 10 minutes googling and cross-referencing to find an alternate explanation. The best hypothesis so far is that she’s a vampire. 
Wow. I wonder how she’d talk dirty? “If I may be so bold to interrupt, I think that my orgasm may be imminent”.
I’ve been in love with Jen Tilly for over two decades. She is still the top of the list (although there are some unflattering photos out there - but I forgive her. After all, she is 50).
I second Dana Delaney. Yowza.
Michelle Pfeiffer is still way hot.
Vampire.
Bathes in the blood of young sopranos.
Jane Seymour (57) still looks good.
The OP is the correct answer.
WOW! I had no idea jennifer tilly was that old, or even close! I thought she was half her age, literally.
The picture of Helen Mirren was taken this last summer. Its a good one in that the bikini is proving that a formal gown in not hiding much, but she has photographed in similarly stunning fashion at red carpet events for the past few years.
Helen Mirren might have maintained a decent body, but her face is quite old looking, unlike the others named in this thread.
I suspect some of these women are members of the Howard Families, and that they are slowly easing us into the end of the Masquerade.
Actually, going by the title of the OP and not the how-does-she-maintain-her-youth question, I think Helen Mirren was a *hotter *50 year old than Tilly is. But that’s *because *she looked older than Tilly does. Mirren defies the young=hot, old=asexual rule of Hollywood. Tilly still looks like she might see your manly bits and giggle uncertainly. Mirren looks like she’d know just what to do, and it might be something you’ve never even heard of, young whippersnapper!
See also: Sophia Loren, Bridget Bardot and Fanny Ardent, all of whom are/were, IMHO, hotter in their later years than their years as generic young sweet things.