Miller, still only 36, broke into Martin O’Neill’s Celtic first-team back in 2003, scoring several high-profile goals including against Lyon and Anderlecht in the Champions League group stages.
He signed for Sir Alex Ferguson and United in July 2004, after the expiry of his Celtic contract, and he went on to play for Leeds United, Sunderland and QPR before coming back to Scotland for a stint at Hibs.
Since the news of his illness broke on social media last night, former team-mates, opponents and fans have been posting messages of support, desperately hoping the ex-Republic of Ireland international can pull through:
The thoughts and prayers of everyone at Celtic Football Club are with Liam Miller and his family at this time. pic.twitter.com/qTOq0v937D
— Celtic Football Club (@celticfc) November 13, 2017
— Home Of Hibs (@HomeOfHibs) November 13, 2017
Awful news about Liam Miller keep the fingers crossed that he somehow pulls through. Was in the USA for treatment this month and flys back tomorrow to start chemo here. He’s still fighting it. Will say a prayer for him tonight. ?? #fuckcancer
— Tam McManus (@The_Tman10) November 12, 2017
Praying for Liam Miller tonight, who is battling for his life. The 36 year old is from the same area as myself. The community is in shock. I will never forget his winner for Leeds against Southampton in 2005 having been down 3-0. Keep fighting Miller ?? pic.twitter.com/bGblBj8bjl
— Barry O' Mahony (@barryomahony4) November 12, 2017
All thoughts and prayers go out to my old teammate Liam Miller tonight
— Chris Sutton (@chris_sutton73) November 13, 2017
All my thoughts and love with Liam Miller and his family ❤️
— Darren O'Dea (@odea_darren) November 12, 2017
Very sad news about one of my old teammates Liam Miller, thinking of him and his family at this very difficult time. ??
— Ian Harte (@ianharte23) November 12, 2017
The thoughts of everyone at Manchester United go out to Liam Miller and his loved ones at this difficult time. pic.twitter.com/CV2zT3xL6y
— Manchester United (@ManUtd) November 13, 2017
Such sad news about my old Room mate Liam Miller, Pray to God he pulls through this battle with Cancer, my thoughts and prayers are with him and his family. ❤️❤️❤️
— Noel Hunt (@Noelhunt20) November 12, 2017
Sad to hear that my old team mate Liam Miller is battling cancer, my thoughts are with him and his family and I hope he can beat this and pull through.
— Alex Bruce (@AlexBruce84) November 12, 2017
Very very sad news to hear that ex Celtic player, Liam Miller is battling cancer at the age of 36. Wouldn’t wish this dreadful disease on anyone good luck Liam pic.twitter.com/zznV9UUGbS
— ANDY LACEY (@knighthawk1970) November 13, 2017
Liam Miller from same area as me, greatest sportman to ever come from here. Going on to play for Cork City, Manchester United, Sunderland, Celtic etc. Absolute legend in my town hope this isn't true, absolutely gutting
— Evan ?? (@FutbolEv_) November 12, 2017
Thoughts and prayers go out to Liam Miller. Tragic news at 36. Was one of my favourite Sunderland players 10 years ago. Tidy footballer & memorable last minute goals v Derby & Boro produced crazy scenes ? pic.twitter.com/FTVf2qqWfI
— Tim Ward (@timmyward) November 12, 2017
Doesn't matter what team you support when someone is battling cancer it's a different story, horrible to see keep fighting Liam Miller, prayers are with you and your family ?
— declan hamill (@declanhamill1) November 13, 2017
Miller had most recently been playing for Wilmington Hammerheads in America’s United Soccer League, following a spell with several high-profile clubs in Australia’s A League.
Get well soon and keep fighting, Liam!