Mark is to leave Erinsborough in the second half of 2011 as McGregor has decided to bow out from the role after less than a year.
In an interview with the official Neighbours website, McGregor was asked whether Mark could eventually return to provide some fresh happiness for his on-off girlfriend Kate Ramsay, played by Ashleigh Brewer.
He replied: "Hmm, he could. His exit has been written so there is a chance he could make a comeback. Who knows, you'll have to keep watching!"
McGregor recently explained that he wants to return to his modelling career, but he has now clarified that he would also like to pursue new acting roles.
"There are still a lot of opportunities in modelling, but I definitely want to continue acting," he said. "I've got the bug now."
The star also paid tribute to Brewer and Scott Major (Lucas Fitzgerald) for their continued support on set.
Asked who he has most enjoyed working with, McGregor replied: "Probably Ash because I didn't expect to click with someone so well and I don't think she realises she has made it a hell of a lot easier for me in my first real acting role - she's taught me a lot. And also Scotty Major has been great, very generous with his time and I've valued his advice along the way."
Brennan's departure scenes are expected to air on Australian screens in August.
> McGregor hints at Neighbours heartache
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