When two major stars collide on the small screen, it either spells disaster or fireworks.

The reason is simple.

Both hold enough weight to head a project on their own, meaning they might cancel each other out as a duo. Furthermore, their celebrity personas can make it difficult for viewers to buy into their characters.

On the flipside, when the chemistry is there a pair of high profile thespians can light up the screen in a way that turns a project to gold.

Viewers will find out what fate has in store for media darlings Lee Seung-gi and Shin Min-a when SBS’ “My Girlfriend is a Gumiho” airs Wednesday night.

Shin earned her acting cred opposite hallyu star Lee Byung-hun in “A Bittersweet Life” (2005) before maturing into a stylista who steamed up a glossy in a Calvin Klein Jeans spread and nabbed the title of “Hot Fashionista” at the 2009 Mnet 20’s Choice Awards.

Lee debuted as a singer at 17 and proved his mettle as a lead actor in the hit SBS series “Brilliant Legacy” nearly five years later. Lee is currently co-hosting SBS’ talk show “Strong Heart” while continuing to tough it out on KBS’ popular reality segment “Two Days and One Night.”

In the upcoming series, Lee plays a rich brat who finds himself tethered to a gorgeous yet frighteningly carnivorous nine-tailed fox, endearingly portrayed by Shin. 

Scripted by the Hong sisters Hong Jeong-eun and Hong Mi-ran -- known for their modern or fusion-style adaptations of Korean fables into dramas like “Sassy Girl, Chun-hyang” (2005) -- “My Girlfriend is a Gumiho” riffs off the traditional tale of the nine-tailed fox (called “gumiho” in Korean), a creature oft-depicted as a femme fatale that feeds on human livers.

“When I first saw the script, gumiho was very different from how I had imagined her,” Shin said at the drama’s press conference last Wednesday. “She was like a newborn child.”

“She is just innocent and wants to be human,” the 26-year-old actress said. “I have a six-year-old niece and am modeling my character after her.”

Shin discards classic feline sultriness for puppy dog cute in the upcoming drama; a move that recalls Daryl Hannah’s squeaky and adorable mermaid in the hit 80s flick “Splash.”

“I am a lovable fox,” Shin said.

Aside from a fondness for meat -- hanwoo (Korean beef) in particular -- Shin’s gumiho, or to be more accurate, Miho, bears little resemblance to the frightening fox of horror series past. But that doesn’t stop Lee’s Cha Dae-woong from trembling with fear when Miho latches herself onto him.

A theater and film student with a wealthy background, Cha rescues Miho from a 500-year-old bond only to have the favor returned when the grateful nine-tailed fox saves him with a magical kiss (Miho passes a life-giving orb to Cha from her lips to his).

“It was not scripted as a kiss scene but the director turned it into one, so I had a fun time filming,” Lee grinned.

“While it is a kiss scene, I was giving him life with an orb. It was not an expression of love,” Shin clarified. “Because it was the first episode, I did feel a little embarrassed.”

Lee, who received the synopsis last year, expressed confidence in his role as an aspiring action star, discussing how he had received action training in the past. He also contrasted his previous stint as an immature rich kid in “Brilliant Legacy” to his new character Cha, saying: “If in ‘Brilliant Legacy’ I played earnest, this time I am comical.”

Comedy is not the only genre to look for in the upcoming series. According to Lee, “My Girlfriend is Gumiho” has melodrama, action and comedy.

“It has everything in it but eroticism,” he joked.

“My Girlfriend is a Gumiho” airs Wednesday night at 9:55 p.m. on SBS.

By Jean Oh (oh_jean@heraldcorp.com)