To Rai Kannu, 36, he and Jack Ho are always in sync, both on stage and off.
He says: "We hang out often and aside from work, we see each other all the time. I think we've grown to become even beyond good friends. Jack and his wife are like family to me."
His bond with Ho, who he describes as "a rolling ball of energy, a Duracell bunny", has become stronger since they got to know each other in the late 1990s.
He says: "I think we started out just as a musical partnership but over the years, we've grown to complement each other. What I lack, Jack makes up for me and what Jack lacks, I make up for him. We fill each other's gaps, especially as a band."
Referring to Ho's marriage to Angelina Leong in 2009, Kannu adds: "My name is in his wedding certificate as a witness so I guess you can't get any closer to another person than that."
Kannu, who is single, has music in his blood.
Veteran blues musician Siva Choy, who is best known for early 1990s comedy album Why U So Like Dat, as well as James, who with Siva formed 1960s singing duo The Cyclones, are his mother's brothers. Tabla player M.S. Maniam, well-known for playing along with international DJs at nightclub Zouk, is his aunt's husband.
Still, the former Raffles Institution student says that while he had watched his uncles perform when he was young, they never directly inspired him to pick up music. It was his mother, a housewife, who did.
He adds: "My mum always had the radio on in the kitchen while she was cooking. She would listen to The Beatles, The Everly Brothers and Elvis. She also made this mix-tape that I ended up playing over and over again, mostly of songs by The Beatles and Elvis."
Kannu, whose father was a logistics manager with electronics giant Philips, picked up the guitar while he was in Raffles Junior College and sang at school events "for fun".
He was also an enthusiastic sportsman. While serving national service, he tore two knee ligaments and had his medical classification downgraded. Unable to serve combat duty, he tried out for the The Singapore Armed Forces Music and Drama Company (SAF MDC) and got through.
"That was my training ground as a performer where I started as a dancer. A lot of people don't know this, but I learnt ballet, jazz and tap," he says.
"The policy at that time was, until you are comfortable to be on stage as a performer, you don't sing. You are a dancer first. So I was dancing for six months and then slowly started coming forward as a singer."
On weekends, Rai started doing informal jams at cocktail bar No. 5 Emerald Hill.
After finishing national service, he did more regular gigs as part of The Strawberries trio, and later with Ho, while at the same time studying at National Institute of Education. He eventually became an English and physical education teacher at Peicai Secondary School and his alma mater, Raffles Junior College.
He juggled his teaching job with gigs at night and during the weekend until 2008. That year, to devote more time to improving himself musically, and four years after Ho left his day job in marketing to fully concentrate on Jack & Rai, Kannu decided to follow suit.
"Three, four years into our band relationship, I never thought I would quit teaching. Music was just a fun thing for me. But a lot of things unfolded for Jack & Rai. We never sat down and planned, all of this just happened.
"I think it's in our characters to take on opportunities that come along."