Cardiff Blues have decided to play a second successive league game at their former Arms Park home.
The city centre venue, which is next door to the Millennium Stadium, staged last Friday's RaboDirect PRO12 fixture against Connacht.
And the Blues have now announced they will play Ulster there on Friday night following discussions with Cardiff City Council.
Capacity will be increased from 8,000 to 9,000, and it is bound to increase speculation about the Blues' long-term future at Cardiff City Stadium, where they moved to in 2009 after making a 20-year lease agreement.
Blues chief executive Richard Holland said: "The supporters seemed to enjoy being back there, and following negotiations with Cardiff City Council I am delighted to announce that we have raised capacity for this Friday's match at the Arms Park to 9,000.
"As I said on Friday night, there are no long-term plans in place to move back to the Arms Park permanently.
"We still have a 20-year lease in place at the Cardiff City Stadium, and playing these two fixtures at the Arms Park has no impact on this agreement.
"However, some games are more suited than others to be played away from the Cardiff City Stadium. and this is something we will be looking at going forward.
"We have arranged a board meeting for Friday to discuss the rest of the season, and we will be reviewing the situation for the 2012/13 season also."