Lindsay Lohan FaceTimes with 'Mean Girls' Co-Star Jonathan Bennett

Lindsay Lohan touched base with her old "Mean Girls" crush just days after Oct. 3 -- National "Mean Girls" Day -- and they were LONG overdue for a catchup.

We're told ... Lindsay and Jonathan Bennett, who co-starred in the high school movie classic, FaceTimed Thursday after not talking for years.

Jonathan was in NYC when he bumped into a close friend of Lindsay's, who suggested they hit her up on the spot. Lindsay posted a pic of their Facetime convo ... and it looks like there was a lot to smile about.

Jonathan told us Monday he totally lost contact with Lindsay.

Lindsay's all stitched up now and back to work.