"Was in the U.S. for treatment this month and flies back tomorrow to start chemo here".
The Cork native, now 36, is reportedly flying back to Ireland on Monday, where he will begin chemotherapy after undergoing initial treatment in the US.
"I gave him his debut and he played wonderfully well in a Champions League game one evening, he was absolutely outstanding", O'Neill told reporters at today's press conference.
Miller, who won 21 worldwide caps over a 16-year career, broke through at Celtic before he was lured to the Premier League by Alex Ferguson in 2004.
We wish him nothing but the best in his fight ahead, and hope for a speedy recovery.
Capped 21 times for Ireland, Miller also had spells with Leeds United, Sunderland, QPR, Hibernian, Perth Glory, Brisbane Roar, Melbourne City, hometown club Cork City and, most recently, Wilmington Hammerheads in the US.
Very bad news about Liam Miller keep the fingers crossed that he somehow pulls through.
It has been reported that the former Republic of Ireland global is fighting pancreatic cancer, although this is unconfirmed.
The Hull midfielder said on Monday: "Obviously we heard the news, we're unsure about the details, but our thoughts go out to his family and we're just thinking about him and we just hope he can pull through and he's strong".
The Welshman said: "My thoughts are with Liam Miller and his family this morning".