The comedian will host what is described as a "reduced" breakfast offering alongside Glenn Robbins for a fortnight from Monday, December 5 while Sandilands and his co-host Jackie O take their usual holiday.
Sandilands's break was scheduled and not linked to recent on-air controversy in which he insulted a journalist who disliked his new television show A Night with the Stars, the Herald Sun reports.
When asked about the incident, Lee said: "I suppose Hamish [Blake] and I take criticism differently. But everybody has their own way of dealing with things. The way it turns out, [Sandilands] may well disagree with our approach, but it's interesting media viewing."
He added that he keeps in touch with Blake when they are not working together, explaining: "The separation is not too foreign. We always talk, but we don't ask each other's permission to do different things.
"If he's doing a TV show or I'm doing a book we would always talk about it - but it's not like we're married and I want to go on a golf trip."
Nine companies - including car manufacturer Holden - are now believed to have withdrawn their sponsorship from The Kyle and Jackie O Show in the wake of Sandilands's latest controversy.