Midfielder Kenny McLean has completed his move from St Mirren to Aberdeen.
The 23-year-old Scotland Under-21 cap has signed a three-and-a-half year deal at Pittodrie in a move understood to be costing the Dons about £300,000.
Dons boss Derek McInnes said: "I think this is the sort of signing that a club like Aberdeen should be making."
McInnes has also signed Lukas Culjak on a free transfer, with the Croatian defender most recently with Borussia Dortmund.
McLean is a product of the Paisley club's youth system and signed a two-year contract extension in July.
There was recent speculation he was likely to move to England, with a bid from Fleetwood Town rejected in January.
He made 29 appearances this season for the Buddies, scoring seven goals.
More recently he has been used as an emergency striker by manager Gary Teale in the absence through injury of captain Steven Thompson.
He tweeted: "Delighted to have signed for @AberdeenFC can't wait to get started! Like to thank all players, staff and fans @saintmirrenfc for some great years at the club and I wish them all the best."
A club statement on the St Mirren website thanked the player and wished him well.
It added: "When Kenny signed a two-year contract extension with the club last summer he put his trust in St Mirren and agreements were made.
"St Mirren FC, on receipt of the offer from Aberdeen FC, have therefore honoured our side of the agreement as Kenny was keen to make this move.
"He kept his side of the agreement with his performances for the club this season."
And McInnes added: "He's a good young player who is still improving all the time and I think in our team he will go and show how good a player he can be."