Anthony Weiner's Sexting Partner Sydney Leathers -- First Steps Into PORN BIZ

Anthony Weiner's sexting partner could be taking her "talents" to video ... 'cause she was seen strollin' around with Vivid honcho Steve Hirsch this weekend -- and we all know how that story ends.

TMZ obtained video of Sydney Leathers -- fresh off her beachside bikini romp -- getting into Steve's car as she left the Vivid porn headquarters in Los Angeles on Saturday.

It's unclear if the two struck any kind of a deal ... but c'mon, you don't get in the car unless you're lookin' for a ride.