Amanda Bynes -- Guy She's Supposedly Marrying Says, No Way, Jose

Amanda Bynes is getting married ... according to a bunch of blogs. But we found out ... it's all news to the guy to whom she's supposedly getting hitched.

According to various reports ... Amanda's tying the knot with 19-year-old Caleb Pusey (relax, it's French) ... a guy with whom she got close while they were in rehab ... but sources close to Caleb tell us it's absolutely not true.

We're told Caleb and Amanda DID befriend each other ... but he says they never dated much less set a date. In fact ... he says he hasn't spoken with Bynes in months.