When did your baby smile at you for the first time?

My son is 6 weeks old and I think he smiled at me today but I'm not 100% sure if it was real or just gas. My wife says it was definitely gas but I swear he was looking right at me and his face did the thing. Please tell me one of you experienced dads had this happen and it actually turned into real smiles soon after because I'm going crazy waiting for this moment.