The actor makes his screen comeback in mid-July as Karl and Susan's eldest child pays a visit back to Ramsay Street amid a troubled time for the Kennedys.
Malcolm decides to return home to Erinsborough to help salvage his parents' marriage, which faces another rocky patch when Susan develops an emotional connection to another man.
Speaking of his return, McNair commented: "It's great to be back. While there have been a few changes and lots of new faces, mum [Jackie Woodburne] and dad [Alan Fletcher] are still the same, so it really is like coming home."
McNair's original stint on Neighbours ran from 1994 to 1997. He later returned for guest appearances in 2002 and 2004 and was also involved in the show's 20th anniversary celebrations in 2005.
Since then, Jackie Woodburne and Alan Fletcher have often called for a comeback storyline for Malcolm.
The character's latest stint will last for four months and McNair will return to filming next week.
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