Who told the king that laertes is a fine swordsman?

In Shakespeare's play "Hamlet," it is Queen Gertrude who informs King Claudius that Laertes is a skilled sWordsman. She mentions this in Act IV, Scene 7, when discussing the potential threat Laertes poses due to his prowess in Fencing, particularly in light of his desire for revenge against Hamlet. This information adds tension to the unfolding plot and foreshadows the duel between Hamlet and Laertes.