Celtic manager Brendan Rodgers wants to sign two "quality" players to make an impact in Europe next season.
Rodgers can land a domestic treble if Celtic win the Scottish Cup final next month and the manager is already planning for the summer.
"We don't need many but if we can bring in a couple of players of quality, we want to make a mark on Europe next season," Rodgers told Talksport.
"That would be progress for us and just keep the momentum going with the club."
Celtic have already secured a number of the Premiership-winning squad on long-term contracts - among them Kieran Tierney and Tom Rogic - and Rodgers is hopeful that Stuart Armstrong will also extend his stay with the club.
He believes that holding on to this group of players, who are one game away from the club's first treble since 2001, is vital to his longer-term plans.
Celtic reached the group stages of this season's Champions League, and Rodgers wants to improve on that.
"Stuart Armstrong is the one we're with at the moment so we're hoping he'll sign another deal, so that leaves a real good core of the team together," Rodgers added.
After defeating Rangers 2-0 in Sunday's semi-final, Celtic will face Aberdeen in the Scottish Cup final in May.
Rodgers remains hopeful that the team's top scorer, Moussa Dembele, can recover from injury in time to take his place in the cup final starting line-up.
Dembele injured his hamstring in the semi-final, and the 20-year-old is due to have the damage assessed by medical staff today.
"He gets his scan today so we'll see the extent of it," Rodgers said. "We've still got five weeks till the final so there's still a good possibility he could make it."