Speaking to The Daily Telegraph, the TV star explained he was forced to miss filming the finale as his wife, Audrey Griffen was going into labour with their first child.
"In the last week of filming, Audrey had contractions seven minutes apart, so it was going to happen at any moment," he explained.
"I was getting nervous while hanging around the mansion and my executive producer… took one look at me and said, 'Osh, you can't miss this. It will be the best day of your life. Don't worry we will make it happen."
Instead, the production came up with a new format for the final episode to make sure Osher could be there for the birth of his son.
"Everyone banded together and figured out a way to make the show work without me being there for the final moments." Osher explained.
The Ten star and his make-up artist wife welcomed their son, Wolfie on August 23, although he admits it was "odd not to be there" in the finale.
"It is the moment they go off into the wild, and I really like to give them a hug and tell them I am happy for them," he confesses.
"But I am sure I will catch up with everyone once the outcome is out there."