Williams made the promise after a failed stunt left him stranded at the very top of the rig for his encore of 'Let Me Entertain You' in Croke Park last Friday night. The star had to rush back down to the stage to finish the song while his band nervously played on.

After the song, he explained to laughing fans how he should have been lowered to the stage in a gondola, and went on to say that he was disappointed in his performance all night. "I haven't been doing so good tonight, so I'm coming back and doing another show for free.

And on my next show the f**king gondola will work!" he said.

Williams then guided cameras to his manager David Enthoven who appeared on the big screen in Croker giving a thumbs-up gesture to Williams's repeated promise to return for free.

Williams then said that he wished he had started his 'Close Encounter' tour in a village hall rather than in front of 80,000 screaming fans. The Croke Park concert is the first leg of his new 40-leg world tour. He is touring for the first time in three years.

The high-energy show included favourites 'Millennium', 'Angels', 'Rock DJ' and an anticipated rendition of 'Back for Good' . . . a tribute to his former band Take That, who Williams cheekily said he couldn't join on tour because "I have my own hugely successful world tour to do". Lifelong best mate Jonathan Wilkes also appeared for a duet of 'Me and My Shadow' and 'Strong'.

Williams bounded around the stage for more than two hours to the delight of his fans, though it did catch up with him at one point. "I want to know how Mick Jagger does this stuff. I'm 32 and f**king knackered. He's about 105 and still does it, " he said before singing a few bars of 'I Can't Get No Satisfaction'.

Though Williams may have been disappointed with his performance, fans sang and swayed on their feet to the music and fireworks. The cheers reverberated around Croke Park to the final promise: "I'll be back before the end of the year!"

Croke Park wasn't the only sporting venue to be taken over by music fans this weekend, with Lansdowne Road hosting the Eagles last night and again this evening, and rockers Metallica playing the RDS tonight.