The actress will play publicist Zoe Alexander, who is set the challenge of giving Paul Robinson (Stefan Dennis) a much-needed image boost.
Mackinnon started filming her three-week stint on Neighbours earlier this week.
Her episodes are expected to air in Australia throughout May.
Mackinnon received a total of six Logie award nominations between 2004 and 2009 for her role as Stevie Hall in McLeod's Daughters.
Internationally, she is better known for playing Allie Reese in Baywatch from 1999 until 2000.
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