Commenting on 1Cor.12v3, in his Commentary on 1 Corinthians:
"At this point someone asks whether unbelievers have the Spirit of God, when on occasion they sing the praises of Christ in glowing terms. I reply that there is no doubt that they have Him, in so far as that effect is concerned;..."
Calvin goes on to state the difference between regeneration and 'the gift of mere factual knowledge'. He continues his explanation by saying that only God the Holy Spirit can empower our tongues to praise God.