THE Gold Coast private school principal who made a hasty, unexplained departure from St Hilda's last week has returned for a tearful farewell to students.

Dr Julie Wilson Reynolds said goodbye at the Southport school's assembly at the end of the day yesterday, shedding a few tears in the process, according to those in attendance.

Students from Year Seven to 12 were called to an assembly without being told the reason and many were surprised to see their former principal on stage.

"She gave a short speech about how she was sad to have left, she was in Woolongong and going to miss all the girls," one attendee told the Bulletin.

"It was the end of the day. We weren't told she was coming, it was a bit of a surprise."

Her parting advice to students was "be strong and kind and be faithful" before she was presented with a bouquet of flowers.

Dr Reynolds abruptly resigned last Monday after almost three years, with a statement soon after noting she and the School Council had agreed it would be "effective immediately".

Despite no reason for her departure at the time or since, school chairwoman Professor Susan Brandis told parents in a letter late last week to respect the privacy of Dr Reynolds who she dubbed a "self-confessed introvert".

St Hilda's deputy principal Wendy Lauman has been made acting principal and is being tipped to eventually take the top job.

Professor Brandis has said there were "no immediate plans to go to recruitment".