The Chelsea wing-back earns a maiden call-up for Spain, who are due to play Germany and Argentina in the forthcoming international break, following his impressive form for the Blues.
Alonso represented Spain at both Under-19 and Under-18 level earlier in his career.
He has been a regular starter for Antonio Conte’s side this season, scoring seven goals for the Blues.
After moving to Stamford Bridge early last season, Alonso went on to become an important member of the team as we won the Premier League title.
Alonso’s Chelsea team-mate Cesar Azpilicueta has also been named in the 24-man Spain squad.
Spain’s game against Germany takes place in Dusseldorf next Friday, with the match against Argentina scheduled for Tuesday 27 March in Madrid.