According to a People, a source confirmed that the 41-year-old shock-rocker is engaged to the 22-year-old "True Blood" actress.
Marilyn reportedly proposed to his future bride while performing on stage in Paris on Monday.
The duo first began dating in 2006, but split in 2008. After a brief reconciliation they split again, but then rekindled their romance yet again late last year.
In 2007, the actress told Elle magazine that the rocker was "lovely, really human and just amazing. It may surprise you just how healthy and loving our relationship is."
The "Beautiful People" singer was previously married to Dita Von Teese.
Reps for Marilyn and Evan would not comment on the reported engagement when contacted by the mag.