These days, it’s not uncommon — and is now even encouraged — to enhance beauty through artificial means. Celebrities have ridden this wave for a long time, and one of the most popular procedures is the infamous breast enhancement. It’s become such a norm these days that it’s hard to even keep track of which starlets have real breasts and which of them don’t. The percentage of plastic is growing, but some celebs — and their chests — stand out more than others. Here are 15 famous celebrities with memorable artificial knockers; before, and after, their procedure.

Heidi Montag

“Reality” celeb turned annoying Hollywood fixture Heidi Montag has gone under the knife quite a number of times for a woman of only 23 years. She was recently quoted as saying how she’s absolutely beyond obsessed with “being perfect.” After she landed her role on The Hills, it wasn’t long after that she sought a nose job and breast augmentation. Fine, she was as flat as a surfboard, and maybe she felt insecure — but she didn’t stop there. In November 2009, she went under the knife for 10 hours to get everything tweaked — from her eyebrows to her thighs. Her rack was pumped up to a DDD cup, and she says she wants them even bigger. Many are saying that it’s now closer to addiction than anything else.