"He's been recording solo and he was about to leave. The Zayn thing was just spur of the moment."
However, the Bye Bye Bye hitmaker thinks Malik's swift move was a good decision.
"I think it was the best move he could have ever done, because Harry Styles is a household name," he explained.
"Zayn Malik - didn't really know his name until he was the first who left the group. So kudos to him for being smart to leave.
"I think the guys are always going to be friends, they're brothers... (but) the fact they lasted this long is a surprise to me.
"Hopefully the other four can go on and do a little more music. I see Harry leaving soon and I don't see another One Direction album happening after that."
Bass is well aware of boy band drama - 'N Sync split in 2002, but ultimately decided to call it quits after Justin Timberlake's solo career skyrocketed.
- WENN