One calls himself a "dirty old man". The other thinks he fully earns the title "the b*****d of radio".
This is how radio personalities develop, they say: You talk and talk and eventually, something happens.
You find something inside you that clicks with the listeners and ego - yes, they freely admit to have plenty of it - takes care of the rest.
For Glenn Ong and Mark Van Cuylenburg, that click happened when Van Cuylenburg (aka The Flying Dutchman) showed off his schoolboy sense of humour and, for Ong, that was when he decided to ignore the rule to not say anything if you do not have anything nice to say.
The insight happened in the late 1990s, when Ong hosted a show at 98.7 FM.
"I knew I would have to stand out. So from that day, I told myself I would have to do the opposite of what everyone else was doing. So I will always be different when I go on air," says Ong, 45.
Van Cuylenburg, 59, called FD by friends and fans, says he knew listeners enjoyed that off-colour sting in the tail, that "little quip at the end of something".
Their styles - snark versus quip, Ong's contrarian streak and Van Cuylenburg's conservative bent - came together on a long-running show on MediaCorp's Class 95 FM, from 2004 to 2013.
Both quit the broadcaster - Ong in January this year and Van Cuylenburg last December - to focus on projects outside radio.
Then, early last month, both were revealed to be co-hosts in the 6 to 10am #1 Breakfast Show. They co-host with Andre Hoeden at competitor SPH Radio's ONE FM 91.3 radio station.
Mr Jamie Meldrum, senior programming director for the rock-leaning ONE FM 91.3, tells Life the station decided to back the duo because their names together mean something to the public, especially for men aged 30 and older that the station is targeting.
"As a duo, they were No. 1 for more than 10 years and, as a brand, they're the best-known radio show in the country. They're also the perfect pairing for what we're doing on ONE FM 91.3, and for guys in particular, they now have a home on a radio station that's built just for them."
On a typical morning, the trio will take on the topic of the day, say, whether e-scooters should be banned, and dig into it.
There is no goal, say the duo, no desire to find consensus or shift the other's point of view. Shows end with no resolution. The point of the exercise is the banter itself.
"The discussion forces people to think, it's forcing people to speak. Too many of us - and I was stuck in that mode for the longest time - just go with the flow," says Van Cuylenburg.
If there is one topic they can agree on and that they both dislike, it is the creeping corporate homogenisation of radio.
It has caused deejay chatter to be cut to a minimum in favour of sponsored product chat, with what is left of the remaining talk stuffed with scripted jokes and pre- planned outcomes.
Scripted talk is a terrible trade-off, they think. What it gains in momentum and snappiness, it loses in genuine emotion.
Listeners prefer radio hosts who come across as real people, even if it makes for the odd dull moment.
Says Ong: "When we go on air, if we are not funny, we are not funny. We don't try to be funny. We've done that for 10 years."
Van Cuylenburg adds: "It's okay to agree to disagree on a topic. It makes for good radio."