Writing on his blog, Robbie – who performs a solo set during each night on the ‘Progress Live’ tour – said: "Oh my lord…Ireland !!!!!!!!!!!!!!!!! What did you do to me on Sunday night…?
"I gave everything I had on Saturday and as expected your performance was better than mine (only just ;) So much so that it was with a bit of trepidation that I made my way back to Croke Park the next day feeling a little jaded and drained from the night before…
(such high highs there has to be a come down)
"But I wasn't expecting what came next. I proper lost my s**t … the overwhelming good will, love, smiles, happiness, approval and acceptance beaming straight to the stage transformed me from preening peacock prima donna showman to a ball of mush within seconds. (sic)"
Robbie – who is joined in the band by Gary Barlow, Mark Owen, Jason Orange and Howard Donald – says the crowds were so supportive, he gets emotional thinking about it and will never forget it.
The 37-year-old pop star – who accidentally flashed his penis on stage on Saturday night - wrote: "It was so powerful that I didn't know if I was going to be able to collect myself … proper floored … there's a tear in my eye thinking about it now.
"Yes, the gigs have ranged from brilliant to religious every night … but Sunday night Croke Park was life defining … it will stay with me for as long as I live. (sic)"