What made Gaga gaga? EXCLUSIVE, EXPLOSIVE, BIOGRAPHY DAY ONE.
It was hard to guess who felt the most uncomfortable. On one side sat a gaggle of uber-trendy fashionistas, on the other a slew of old friends with shaved body hair and fake tans.
The setting was even odder. Gaga - fresh from a hyperstylish Manhattan photo shoot for Rolling Stone magazine - had dragged everyone way out into the suburbs of Queens, New York, on the promise of spaghetti at the home of her boyfriend Speedy's parents.
Initially Amanda Lepore, a transsexual fixture on the New York club scene, thought this was an attempt by Gaga at normality.
"She was super-nice and down-to-earth," Amanda said, noting that the singer was wearing flat shoes. Then as Gaga dished up, she started talking about herself in the third person.
Amanda said: "She was like 'Oh, Gaga would do this,' 'Gaga that.' But not like it was her - like it was a third person. I think she's crossed that boundary."
Gaga's transformation from chubby club crooner to charttopping fashion icon has come at a price.
Her mental and physical health is so fragile she constantly checks into hospital.
Always exhausted, she alternates between bingeing and starving herself.
She can't sleep or shower without someone alongside her in the bed or bathroom. Gaga, 24, can't stand to be alone even for a minute.
It was all so different when Gaga, then plain Stefani Germanotta from New York's posh Upper Westside, started out. "She was going to do whatever it took to be famous," said Wendy Starland, who d i s c overed Gaga 'performing in a grungy Manhattan club and introduced her to top producer Rob Fusari.
"She looked like something out of Goodfellas," Fusari recalled. "She was a little overweight. She looked like she was ready to make pasta at any minute."
Fusari, who had worked with Beyonce and Jessica Simpson, thought it would take too much work to market this Britney Spears fan.
But the classically trained musician, who'd been auditioning for Broadway shows and meeting industry bigwigs for years, charmed him by batting her eyelashes and claiming she was a novice. "I found out later she had really shopped to most labels. It was funny to uncover the truth," he said. Fusari, suing Gaga for pounds 20million claiming she reneged on their production deal, was stunned by her demands.
She wanted an 80-20 split in her favour, beyond ballsy for a 19-year-old unknown. Gaga's internet entrepreneur father Joe acted as her manager - and drove a hard bargain.
But Fusari and Wendy thought their new act wasn't pretty enough to make it. Stefani, as she was still known, put herself on a diet and fitness regime, losing more than a stone in weight.
"I said we can do something theatrical so it's not the attention on her looks," Wendy recalled. "She talked about it too. She was like, 'I know my look is untraditional and I'm not the classic beauty. We have to do other things.'" Wendy spent more than a year working for free on Gaga's songs and image before she won a contract and moved to LA. One Christmas Gaga bought her a Chanel handbag.
But when Wendy asked to be paid for her services, the newly famous Gaga said she thought it was a bit much to expect money for introducing one artist to another. That was the last Wendy heard from her protege.
Dumping those who have helped her has become a habit for Gaga. Ex-tour manager David Ciemny estimates she got shot of 150 staff in 18 months.
And his pregnant wife Angela, who was employed as Gaga's 24/7 personal assistant, quit after being accused of failing to focus on her job while she was suffering morning sickness.
Angela joined the tour at the start of 2009. Gaga had already scored No1 hits across the world with her debut album The Fame, and the singles Just Dance and Poker Face.
What little downtime Gaga had was spent in a tanning booth, watching monster movies and comedy Family Guy, or obsessively checking websites about herself.
Angela was reluctant to take the job at first as she was trying desperately to conceive at the time.
But Gaga promised her that she'd be "really nice" to work for, adding as an incentive: "If you come on tour with me, I'll let you sleep with David so you can get pregnant."
But Gaga couldn't settle without someone next to her in bed and Angela ended up sleeping with Gaga more than her own husband.
On the few occasions Angela tried to return to her husband, Gaga spiralled into a panic. Then the phone would start buzzing.
Angela said: "She'd call and text me, 'I miss you, Ange, can you come back?' And she'd tell Dave, 'Can your wife stay with me tonight?' "So I would sleep in her room because what's the point of going back to my room when I have to wake up in an hour and be here?" By the time the tour reached Australia last summer, Gaga was suffering from perpetual jet-lag and was on such a strict diet she had dropped 20lbs in weight.
She worked herself into such a state that she often begged to go to hospital - just for peace and quiet. Angela urged Gaga's management to give her a break but was told: "Get her to do it. Get her to eat, get her to sleep right now, she doesn't need to take her make-up off, she doesn't need to shower."
Angela says she tried to act as an older sister to Gaga, who spent hours wailing about her lack of a love life. But the friendship soured when Angela finally managed to get pregnant.
Gaga wasn't sympathetic over Angela's morning sickness. After getting told off for failing to pack a pair of tights for a TV appearance, Angela quit.
Her husband claims he took a short leave of absence for paternity leave when his wife gave birth, then discovered he was out of a job when his pay cheques stopped.
When he emailed to ask her what had happened, she responded: "You always have a job with me. I didn't know about this. Let me get on to this. Hugs and kisses, Gagaloo."
David, who had worried constantly about Gaga's fragile mental state and had taken her to hospital on at least six occasions, never heard from the singer again.
Insiders say Gaga has become a control freak who, just like her heroine Madonna, demands perfection. She has also done a pretty good job at re-writing her own life story.
She claims to have been a misfit but her school and university pals say she was boringly normal. If she did take lots of drugs, she hid it - everyone says she was focused on her music.
By the time she evolved into Lady Gaga superstar, she'd added plenty of eccentricities to her act - like the purple teacup she carried everywhere and briefly lost at London's Groucho Club or her pounds 10,000 disco stick. Even so, there are still occasionally a few flashes of the old Stefani. Recalling the dinner party at Speedy's family home in spring 2009, Amanda Lepore says she was surprised by Gaga's choice of untrendy friends, who dressed like the Italian-American stars of the reality TV show Jersey Shore.
"They had fake tans. One of the boys had tweezed eyebrows and shaved body hair," she said. Perhaps most surprising of all, Gaga actually cooked spaghetti. For despite Gaga's megastardom, at heart she is still the Catholic girl from the good Italian family, who says that a part of her really wants to find a nice man to marry and serve him dinner each night.
But, as we shall see tomorrow, that dream has been shattered by every man she's ever loved.
ADAPTED from Poker Face: The Rise and Rise of Lady Gaga by Maureen Callahan, which is published by Hyperion and is out on October 14.
TOMORROW: The constant heartbreak
MUG Purple cup Gaga became obsessed with GROSS Beady eyes.. and face ENERGY Performing exhausts her HAIR-RAISING Over-the-top outfit SOLAR-POWER Shiny SHADING IT Bizarre sunglasses MISS WHIPLASH With subtle collar FIERY Sparks fly when Gaga gets on it CALL ME A look to dial for CANNY Let's drink to that CUDDLY In 2004 with pal FRESH-FACED Gaga, front left, with school mates back in 2004