She had previously described Clancy's approach to wedding planning as "really chilled," and confirmed everything had been "on track" in the lead-up to the big day.
Lynne and partner Paul are thrilled for Clancy and Luke
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Lynne, 70, did admit she was taken aback when Clancy told her she was engaged, and thought she was "taking the mikey".
Her long-term partner Paul McWatersalready knew as Luke had asked his permission.
This mother daughter duo have a whole lot of love for one another
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"I remember [Clancy] FaceTimed me and said, 'So we've got a bit of news,'" Lynne recalled.
With a laugh, she added: "I thought she was pregnant, which I wouldn't have minded."
"Clancy saw the look on my face and went, 'No mum, I'm not pregnant but...' and she lifted up her finger with the engagement ring on it."