The couple reconciled in June 2012 and Harris moved back into the Playboy Mansion.
A Playboy source confirmed to E! News that Harris, who had called off the wedding in June of last year, and Hefner are again making plans to marry.
No date for the event was specified.
"Dear past, thank you for all the lessons. Dear future, I'm ready," Harris tweeted recently.
2014: The Year in Music [PHOTOS]