Saw that someone looking for this information came in here, to a post on A-do's Taiwan autograph session instead. Thanks for your interest! :)
They have been announcing the date, time and venue on Y.E.S. 933 lately, so stay tuned there. What I did find online is that the session will be on 30 October, next Saturday. It's also stated on the 933 website that he will be attending the Singapore Hit Awards on 29 October, next Friday.
Just thought I could help to answer this. Although A-do and Jeff are no longer in OB together (
A-do didn't renew his contract earlier this year, and I heard Jeff has set up his own company), Jeff is after all a good singer who deserves our support. :)
Update: The event will be held at City Square.