Head coach Joe Schmidt had his appendix removed after Saturday's victory over Australia, an Irish Rugby Union (IRFU) statement has confirmed.
"Following yesterday's game against Australia, Ireland head coach Joe Schmidt was assessed by the match day doctors and was sent to St. Vincent's Hospital for further assessment," read the statement. "On Saturday night Joe had his appendix removed and is recovering well this morning. He would like to thank the doctors and nurses of St. Vincent's Hospital and everyone for their well wishes and kind messages of support."
Schmidt gritted his teeth through Ireland's 26-23 victory over Australia in Dublin, then headed straight for medical tests suffering suspected appendicitis.
The former Leinster boss kept his counsel on his illness to guide Ireland to their first autumn Test series clean sweep since 2006.
Ireland opened their autumn series by seeing off South Africa 29-15, before fielding a largely second-string outfit that eased past Georgia 49-7.
Simon Zebo and Tommy Bowe claimed tries as Ireland raced into a 17-0 lead against Australia in Dublin on Saturday.
The visitors hit back through Nick Phipps' brace and a further try for Bernard Foley, only for Ireland to fend off a second-half onslaught and grind their way to victory.
At the final whistle, rather than fulfil usual media and other commitments, Schmidt headed off for further examination with medics offering a tentative appendicitis diagnosis.
Ireland captain Paul O'Connell said after the game that without prior knowledge no one would have realised Schmidt was battling a nasty illness.
"Guys were aware he was sick, he was kind of stand-offish, he was worried about passing on anything he had," said O'Connell. "If you hadn't have been told, I don't think anyone would have known."