South Korean television drama fans who would like to see stars Song Joong Ki and Song Hye Kyo re-create their sizzling chemistry in last year's hit series Descendants Of The Sun will just have to watch the show again.

The chances of an on-screen reunion for them are slim, since they will be married soon and he thinks it would be tricky to mix their work and personal lives.

"Working with Song Hye Kyo in the future, I would have to give a little more thought (to it). It may be challenging because work is work. It may be a little tough to work on the same production," he says, speaking through a translator at a press event here yesterday.

The much-anticipated wedding of the celebrities will take place at The Shilla Seoul hotel on Oct 31.

Ahead of the wedding, he visited Singapore to promote his new wartime movie, The Battleship Island. At the press conference at Marina Bay Sands, he was joined by director Ryoo Seung Wan and his co-stars Hwang Jung Min and So Ji Sub. They were also scheduled to meet fans at a public event at Suntec City yesterday evening.

The Battleship Island, a highly anticipated World War II drama, is Song's first production after rocketing to superstardom with Descendants Of The Sun, where his army captain character romances a beautiful doctor (Song Hye Kyo).

In the new movie, Song Joong Ki, 31, plays yet another heroic soldier.

He says: "If you count the number of years - I served national service in South Korea, as well as played the role of a soldier in Descendants Of The Sun and The Battleship Island - I've been living the life of a solider for about five years now.

"It has become natural to me. I had short hair after serving national service, so I could comfortably immerse myself into the role."

His Battleship Island character is a special forces agent with the Korean Liberation Army, sent on a mission to a forced labour camp on Japan's Hashima Island, known as Battleship Island, during World War II.

Based on historical accounts, the thriller delves into the tragic plight of the captive Korean labourers, toiling away in a coal mine.

The inspiration to make the blockbuster - which has a star-studded cast and was produced on a massive budget of 22 billion won (S$26.6 million) - came when the director saw a photograph of the island in 2013.

Ryoo, 43, says: "The image was so powerful. It was so overwhelming. when I found out the history of the island. I was really moved to bring the story to the public."

Song says one of the challenges he faced in playing one of the malnourished labourers was having to lose weight, and the most memorable scene to film was one in which the workers attempt to escape the island.

"It was not only because of the fast images and the cinematography, but also because of... the suffering of the captive labourers," he explains.

Out of the three actors, who would be able to survive such harsh conditions and make it out alive?

Actor So, 39, chooses his younger co-star Song, saying: "Song Joong Ki probably has the best survival skills. He recently served his national service, so the memories of skills and training are fresh in his mind."

Hwang, 46, chimes in: "For the rest of us, any big, intense movement would cause pain."

•The Battleship Island opens in cinemas on Aug 17.