Gu Hye Sun says that working with a younger actor is making her feel self-conscious about the way she looks and the state of her skin. But at 30, the actress is barely three years older than her "Blood" co-star Ahn Jae Hyun.

It could be that Ahn looks so much younger than he is. Or it might be because he played Jun Ji Hyun's younger school-age brother in "You Who Came From The Stars." But acting scenes with Ahn is making Gu Hye Sun worry about her wrinkles.

At a press conference for the vampire medical drama Gu revealed that she was wearing more make-up and making more frequent trips to the dermatologist.

"As the wrinkles on my face have gotten deeper, my makeup is getting that much thicker," she said. "I don't usually make visits to the dermatologist but I've been going more frequently. I've been reading booklets on cosmetology and taking more interest in it.

She credits her model-turned-actor co-star as being the reason for her increased interest in looking young.

"Acting with Ahn Jae Hyun, who is younger than I am creates some pressure."

At that point he interrupted her and pointed out how close in age they were.

"A younger guy who isn't that much younger," he said.

Netizens don't agree that she has to worry about wrinkles just yet. When she posted a selca of herself with two of her dogs in November of 2014, netizens commented on how much younger she looks than her age.

It's also interesting that Gu Hye Sun feels overwhelmed when working with a rookie actor when she's had some intimidatingly handsome co-stars in the past. She acted opposite Lee Min Ho in "Boys Over Flowers," Daniel Choi in "The Musical" and Lee Sang Yoon in "Angel Eyes." She's not only attractive but also pretty impressive herself. Her many talents include writing books and directing films.

In "Blood," Gu Hye Sun plays Yoo Ri Ta, a blood cancer specialist and an heiress. Blood is the thing she has in common with Ahn Jae Hyun's character. In his first leading role, Ahn Jae Hyun plays an eternally good-looking vampire who is also a surgeon. His character has learned to curb his thirst for blood in the interest of helping humanity. The drama also stars Jin Ji Hee, last seen in "Warm Words" as their chief.

"Blood" is produced by the same writer and director responsible for the hit drama 'Good Doctor."