One of McLachlan’s accusers, former co-star Christie Whelan Browne, is also named in the suit, according to media reports.
The Seven Network says McLachlan’s statement of claim was lodged in the NSW Supreme Court on Thursday afternoon and principally targets Browne.
McLachlan has engaged prominent barrister Stuart Littlemore QC to run the case, News Corp Australia reports.
A Fairfax Media and ABC joint investigation in early January reported several cast members of the 2014 run of The Rocky Horror Show accused the 52-year-old of touching or exposing himself to them.
A woman and a man who worked as part of the crew have also gone to Victorian police who are investigating the allegations.
McLachlan previously described the claims by Whelan Browne, Erika Heynatz and Angela Scundi as “baseless” insisting they were “all made up”.
After the allegations were aired McLachlan withdrew from the current production of the Rocky Horror Show in Adelaide.
Fairfax Media and the ABC on Thursday told AAP they wouldn’t be commenting on the legal action.
Littlemore said he would “absolutely not” be commenting.
Comment has been sought from Mollison Keightley Management which represents McLachlan.
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