Being surrounded by celebrities all day might seem like a dream come true, but when you're the one in charge of making them look flawless, one can only imagine what's seen when the cameras aren't rolling. In general, applying makeup isn't an easy task, and when it's an artist's responsibility to make a star look their best, the pressure is on. While most celebs have loyal makeup artists who they have created trusting relationships with over the years, there are other makeup pros who only work specific shoots and gigs that have seen some very interesting things.

First things first: an artist has to be really good at what they do in order for an A-list celebrity to trust them with their face - and it can take years and years of practice before an aspiring makeup artist becomes somebody celebrities actually want to work with. While many have no problem sharing their stories, most do remain nameless for the sake of the stars' privacy, but it's crazy to hear what it's really like being a celebrity makeup artist!

While it's obvious a pro must be consistent, what many people don't realize is that they have to also be quick. "Beyoncé told me once, 'The bad thing about being good is no one is going to give you more time' - and she was right," makeup artist Sir John told Cosmopolitan. "When you're speedy and good, everyone expects the makeup to be on like bippity boppity boo - magic." He went on to explain how he spent a lot of time practicing on girls in clubs since most of the time he only has about 20 minutes to do a full face of makeup. "I used that speed to my advantage," he admitted. "And now I'm one of the quickest guys in the business."

Since not all makeup artists are fortunate enough to work with clients like Beyoncé, there are some ugly truths when working with different celebrities. "You wouldn't believe how many celebrities have acne - like severe acne," an anonymous artist told Cosmopolitan. "They have to wear so much makeup for the camera, their skin can't breathe and their pores get clogged. I once did a hair commercial with a young, up-and-coming actress who came to the studio with makeup already on, but I didn't realize how much until I started wiping it off. She'd layered it on like peanut butter in an attempt to cover the giant zits all over her face."

She went on to describe a time when an "incredibly famous model" showed up to a shoot with a hairy upper lip that she had to bleach and then shave on the spot because it showed up in all the photos. "The model was so embarrassed she started crying," revealed the makeup pro. "I told her it wasn't bad, but the truth was, it was the gnarliest mustache I'd ever seen."

"The thing is, even the most perfect-looking stars have just as many insecurities as the rest of us," she added. "They'll ask things like, 'Can you make my nose look smaller?' or 'You can make my upper lip bigger, can't you?' I can't blame them; their face is going to be plastered all over the big screen, ads and magazines, and they know they're going to be scrutinized."

Apparently she's not alone because another anonymous makeup artist shared similar stories. "A lot of people think the job is all glamour, but that's not necessarily the case," the artist told Refinery29. She then went on to explain how she was once asked to do an unnamed celeb's makeup in a helicopter because she was running late for an event. "I was like, 'A) I'm afraid of heights, B) I might throw up, and C) This is ridiculous," she recalled. "I just put my foot down, finally, and told them they were crazy. I ended up doing her makeup in five minutes, adding a little eyeliner, a pop of blush, a lip color and some good concealer. You have to be quick on your feet."

This anonymous artist also explained that, often times, her clients aren't considerate and will sit there during early morning shoots and have the nerve to order themselves coffee and breakfast without even ordering her anything. "Or, sometimes, a publicist will call me at 5 p.m. the day before a 9 a.m. job when I'm already working, and they'll ask me to run to Barneys to get the client her favorite Cle de Peau concealer," she added. "Once, someone told me their client was a germophobe and that I needed to bring brand-new makeup brushes... at 4 p.m. the day before a job."

While it can be tough, it does have its perks. "But, look, this job can be so great," she concluded. "A lot of times, I've worked with young actresses only to see their careers blow up. I once started working with one young woman and the money was just okay, but I loved her and her team, so I stuck with it. Then, the press started writing about her everywhere she went, which was amazing for my career... It's always good to work with someone who has potential. Someone once told me to find my muse, and I'm glad I learned that. Everyone will always chase after Angelina [Jolie], but I believe in the actresses I've worked with and the projects they've worked on, and it's paid off. It sounds naïve, but it's true: As an artist, when you're inspired, you'll be better."