The former Westlife star was due to play the Odyssey Arena in Belfast on Sunday, May 25, and Monday, May 26, as support to the recently reformed Boyzone.
But the singer has just signed a record deal with Universal in Australia, which means his album will now be released there in May/June this year, clashing with the Boyzone dates.
Brian said: ” I am really sorry to have to cancel my support on the Boyzone tour. I was so looking forward to playing the songs from my new abum live on this tour but the opportunity to get on with releasing my album in Australia is too good to miss.
“I’ll be back in Europe in the summer with a view to releasing my album and playing some dates.”