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The national airline of Turkey is giving female flight attendants a bit of fashion advice: No red lipstick or nail polish.

It's actually more of a directive, which has struck a nerve among secular Turks who worry that the country is becoming more Islamic, according to Reuters.

But Turkish Airlines told Reuters the move was about "improved communication with passengers." The more natural look of pastels, it seems, accomplishes this.

"As a consequence of our current cabin uniforms not including red, dark pink, et cetera, the use of lipstick and nail polish in these colors by our cabin crew impairs visual integrity," the airline said in a statement to Reuters.

Turkish Airlines did not respond to ABC News' request for comment.

Turkish Airlines scrapped its own ban on headscarves more than a year ago, and covered women now work at check-in counters and at other positions in the company, according to Reuters.

The airline banned alcohol on some flights earlier this year. Islam prohibits the consumption of alcohol, and the vast majority of Turkey is Muslim.

But the airline is far from the first to put fashion restrictions on its flight attendants. Asiana Airlines prohibits its female flight attendant from wearing pants. The airline also has specific rules regarding hairstyles and makeup.

In March, Bangkok-based Nok Air posted an ad looking for females aged 25 and younger; at least 5 feet 3 inches tall; proportionate in their height and weight; and not wearing dental braces.