The New York Police Department had been drafted in, security was air tight and not a sinner was getting past the backstage door.

But then again this was America and the Irish would always help each other out. As throngs of screaming fans were kept back and a line of blacked-out SUVs got ready to whisk U2 away, a pretty girl from the west of Ireland stuck her head around the door.

"I've travelled from Ireland this morning and I have to get a couple of lines off the band, can you help me out?" Without a second thought she had me through the golden gates and up the stairs to the band's private dressing room.

On Sunday night U2 had descended to help fulfil the childhood dream of their Irish songwriter pal Gavin Friday. It had been over 30 years since Gavin was asked by a bewildered young Bono why he thought they should perform at Carnegie Hall when they came of age.

"Because it's the most magical room in the world!" Gavin had exclaimed.

Three decades later a somewhat more worldly Bono was standing centre stage introducing his lifelong friend to the crowd in the run-up to his 50th birthday. Beaming, Gavin bounded over and gave him a playful nudge on the shoulder while the spectators, looking on from the famed red and gold surroundings, burst into applause.

Throughout the night The Virgin Prunes' luminous performance was interwoven with a bevy of showbiz elite who had come down to tip their hat to the punk renaissance man.

Scarlett Johansson performed in knee-weakening sultry tones; Courtney Love gyrated in Gavin's honour, legs locked around his waist while kissing his face; and Shane MacGowan -- who received one of the biggest ovations -- sauntered on stage, whiskey bottle in hand, to deliver a legendary performance of A Rainy Night in Soho.

Supermodel Christy Turlington was leaning against a nearby wall backstage also waiting for the band to surface.

"I've known Gavin for 20 years now. He came here for his 40th and that was a huge celebration too. This has been talked about for a long time and it's great that Bono can make a dream like that come true," said the stunning catwalk queen.

Here's hoping he can work a little magic for me too, I thought as bedlam suddenly came hurtling towards me.

It was an American PR woman, over in a panic, asking how I had evaded security and ushering me out the door. "It's fine, one line from Bono and I'm gone," I protested to no avail when suddenly the great man walked by.

"Bono I've travelled from Ireland this morning, I just need one line," I said as he shook my hand through the moving crowd. He took one look at the fuming PR woman: "Sorry I can't," and with that he was gone.

Back outside on the cold street I was wondering what on earth I was going to do. Then who comes out a side door only Larry Mullen Jnr. And even better still, he seems to have all the time in the world.

"It was great to do it for Gavin," he tells me. "He has been a friend, compatriot and collaborator for such a long time so this is an opportunity to show him some love."

In a nod to Friday's influence behind the band, he goes on: "Gavin has been our collaborator and our harshest critic and we need that. It's never tough to take from him. He's always balanced, fair and harsh, and that's OK."

I ask if it's true that the band will be rounding off the phenomenal success of their 360° tour in their home country. "I'd like to finish it in Ireland . . . Personally I would love to play in Belfast. I don't know if we'll be able to achieve it but there have been talks."

Any particular time-frame in mind? "Maybe September," he says with a knowing smile.

Speaking about the "general feeling in the air" in Ireland, the legendary drummer explains how being successful and wealthy is not a flag that is proudly flown in his home country.

"I feel if you're successful in Ireland in some respects you're made feel embarrassed . . . and anyone who is successful, they'd almost mark an X across your door in blood. It's as if you've done something wrong in making your money and it's unfair."

Despite the negative feelings, he says he'll never leave the country he loves.

"I'm not going anywhere. I'm staying in Ireland, my kids are there, I love living there and I won't let that other stuff get to me."

Back at the intimate bash, the shabby-chic exterior of The Spotted Pig gives little indication that the Manhattan hang-out is bursting at the seams with the hottest crowd in town.

Shane MacGowan is drinking hot whiskey and singing the praises of Sinead O'Connor.

After receiving several thumbs up for this performance on the night he talks about "the ghost of my first girlfriend" who came to him the night he penned Rainy Night in Soho in the confines of a dingy bedsit.

"For my funeral though I'd like them to play I'll Take You Home Again, Kathleen," he muses.

He also takes his hat off to Lady Gaga's routine on the night: "Even when you don't look at her, you still enjoy the performance," he chuckles in his famous mouthy laugh. She was certainly one of the highlights of the star studded affair.

Upstairs in the pub, wearing nothing but killer black stilettos and a sheer leotard with two blacked-out crosses covering her breasts, she strutted across the floorboards to where Gavin Friday was sitting and presented him with his cake.

As 50th birthday presents go, it had to be one of the best. But then when you're Gavin Friday, former punk Dadaist and best friend to Bono -- it's just another day in the scintillating world of U2's inner-circle.

Mind you, it wasn't the first favour Lady Gaga had granted to Bono last weekend. In a phonecall the night before he had asked the world's most sought-after popstar to perform at Carnegie Hall as part of Friday's milestone celebrations. Lady Gaga, who had practised ballet at the grand theatre when she was only five years of age and turned pages for her music teacher on the same stage at the tender age of 11, was obviously getting the chance to fulfil a childhood dream of her own too.

"When I spoke to Bono he was like 'oh it's just this little downtown thing'," explained a bemused Gaga (she prefers people to drop the 'Lady' in daily conversation).

"And I'm thinking to myself as I arrived here [at Carnegie Hall] tonight: 'This isn't 'downtown' to me!'

"But I guess when you regularly play to 90,000 fans it might feel like 'downtown'," she quipped.

Also at the party, and donning a white straw hat, renowned Irish novelist Pat McCabe chatted about the danger of writing scandalous prose for the sake of shock-value itself, while someone who loves to do just that -- rock musician Courtney Love -- walked by looking unusually well-behaved.

The former love of the late Kurt Cobain later tweeted: "I have kissed a lot of rock stars in my time but seriously never so many as the last 24 hours."

As the party got into full swing, Bono worked the room among the likes of Johnny Ronan, Robbie Fox, businessman Oliver Caffery, Dunnes Stores heir Andrew Heffernan and former manager of Hothouse Flowers Robbie Wootton.

After a short while he sat down in the corner to chat to some friends and his beautiful wife Ali took a seat on his lap. Having recently celebrated a landmark wedding anniversary, the two appeared to be as inseparable as ever.

Later I ask the secret behind the long-lasting marriage to his childhood sweetheart, "After all these years she's still a mystery to me," he says with a simple but ever-romantic reply.

I tell him I'm sorry for crashing his dressing room -- put it down to the pressure of getting a line -- and he says it's OK as we chat about the night and what a superb job Hal Willner did in putting the show together.

Then, just as the party is really getting into the flow, the tough PR woman is back and demanding that I leave at once. After some protestation, I am about to reluctantly submit when the most unlikely of saviours, Shane MacGowan, tells her that I'm a good friend of his, and to leave me be. With that she turns on her heel and I'm left to party the night away with Shane and Co in this once-off Fairytale of New York.

Sunday Independent