The European Court of Justice (ECJ) is due to deliver its verdict on the Scottish Government's plans for a minimum alcohol price.
Judges at the Luxembourg court will give their ruling on the proposal for a minimum unit price of 50p following an interim opinion from ECJ advocate general Yves Bot in September.
Mr Bot concluded the policy would only be legal if it could be shown to be the most effective means of achieving the desired public health benefit.
His opinion was welcomed by both sides of the debate, with First Minister Nicola Sturgeon insisting it confirmed minimum unit pricing is not precluded by European Union law.
The Scotch Whisky Association (SWA) said Mr Bot had backed up its view the policy is illegal when "less trade-restrictive measures" were available.
SWA officials mounted a legal challenge alongside other European wine and spirits producers after legislation to introduce minimum pricing was passed by the Scottish Parliament in 2012.
The legal bid was initially rejected by judge Lord Doherty at the Court of Session in Edinburgh in 2013.
Following an appeal hearing, the case was referred to the ECJ last year for its opinion on six points of European law.
A hearing took place in May before the advocate general and court judges, who have been considering Mr Bot's opinion before giving their ruling.
The case will be referred back to the Court of Session for a final decision, likely to be in several months' time.