Simon Cowell kicks up his high heeled custom-made boots after partying at book launch

He was probably a little nervous turning up the launch of his 'unauthorised' tell-all biography.

So when it was all over, it was time for Simon Cowell to party.

And it looked like the X Factor supremo had had a good night.

Good night? Simon Cowell looked a little worse for wear last night as he headed home from partying in Mayfair after attending the launch of his unauthorized book earlier in the evening

The 52-year-old was pictured looking a little worse for wear, slumped in the back of his chauffeur-driven car after a night at the Arts Club in Mayfair, London.

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He heavy-smoker clutched a packet of menthol cigarettes and smiled widely.

But he still looked perfectly groomed in a black suit and tie.

And he unwittingly revealed his heeled Cuban shoes - handmade by cobblers Berluti in Paris - which he often sports but usually has his trousers tailored so they are rarely seen.

The black leather, lace-up shoes, along with his spiky haircut, give his 5ft, 7in frame a boost of three inches.

They reportedly cost £1,000 a pair and he has said that when he goes shopping, he will always buy five of everything.

He always wears his trousers over-long, to hide the heels

More secrets of his beauty regime and quest to stay young have been revealed in his book, including regular botox injections, vitamins fed through intravenous drips and regular colonic irregation.

Simon earlier posed with author Tom Bower, who penned Sweet Revenge: The Intimate Life of Simon Cowell.

The star had turned up to the book launch at the Serpentine Gallery.

Simon spoke at the launch and apologised to his close friends and family for embroiling them in the drama that came with the book.

It had detailed his secret affair with Dannii Minogue, his break-up with fiancée Mezhgan Husseiny - and how he had wanted a fling with Cheryl Cole.

The star admitted he had spent the past week 'hiding under a pillow... I knew it was bad because  friends were sending sweet messages asking me "are you ok?"'

Home bound! The X Factor supremo clutched a packed of menthol cigarettes in the back of his car

Dressing up: Simon looked dapper in a suit and tie

He said; 'I wish to publicly apologise to anyone I embarrassed.

'I do have to apologise to members of my family.'

However, he added; 'Ten years ago, if I had read someone would be writing a book about me, saying I'd made loads of money, shagging loads of girls, I would have said "great".'

Surprise! Simon attended Tom Bower's book launch of his unauthorised biography Sweet Revenge: The Intimate Life of Simon Cowell at the Serpentine Gallery in London