For country singer-songwriters Mel Ferdinands from Singapore and Rani Tofani from Indonesia, their cross-border musical pairing started out via a WhatsApp group chat.

The duo, who perform as Rani & Mel, will be playing two sets at the Esplanade Outdoor Theatre tomorrow, backed by a band they named Indopura.

In 2015, both were added to a group chat created for artists who were playing at the Miri Country Music Festival in Malaysia.

"We had never met and when I saw the name 'Mel', I thought 'Oh, it must be a lady.'" Rani, 40, says.

They bonded over their similar sense of humour, says Ferdinands, 58.

"I think we were the loudest people in the group chat, always making jokes."

Their music output is no laughing matter, though. They finally met at the music festival and a mutual jam there led to plans for a deeper collaboration, as well as more shows together in the region.

To date, they have gigged in Singapore, Indonesia, Malaysia and Myanmar. They have also performed on several television programmes in Indonesia.

The pair are also hoping to travel even further for shows next year. They are planning for gigs in Britain and France. An album of original tunes is also in the works. It includes songs which they wrote individually, as well as tunes they worked on together.

The audience at the gig tomorrow will get to hear some of these songs. The show is part of the Esplanade's series of free performances this month called Celebrate December.

Some of Rani's songs are sung in Bahasa Indonesia, such as Lagu Untuk Mu (Song For You), which she wrote for her late sister. The rest are in English.

"I'm not a romantic," says Rani, who is married with two daughters. "When I write about love, it's usually about universal love."

Of their tunes, Ferdinands says: "Even though we are both known for playing country music, our songs are not typical country songs. Our music has a lot of pop and rock elements in them."

Ferdinands is a familiar name in the local music scene, having made his debut with his brother Joe when they were children in the early 1970s.

In the 1980s and early 1990s, the duo, together with two other brothers, Dixie and Don, were also part of pop-rock band Gypsy and played regularly at popular nightspots such as Peppermint Park, Rainbow and Gazebo.

Gypsy is set to do a reunion show at the Esplanade Theatre Studio on March 11.

Rani, who is based in Jakarta but grew up in Sukabumi, West Java, is known for playing in bands including Rani And Westom Country Band as well as Sweet Hurricane.

Ferdinands says: "What struck me the most about Rani is that her singing style sounds so natural. She doesn't sound like she is trying to imitate anyone."