What must it be like to have unlimited funds to spend on whatever you wish? Would you socialise and shop till you drop or work tirelessly for charity? One woman who faces this dilemma every day is 25-year-old Yuki Oshima-Wilpon, a 'billion-heiress' who lives in a five-storey, five-bedroom house near Harrods with her husband Bruce, 27, a playwright and musician, whose own father made millions on New York property. Yuki's whole lifestyle is funded by her billionaire father, a Japanese financier. So does her privileged life make her a spoilt little rich girl? We asked her to keep a diary for a week to find out... MONDAY: 11.50am One of my two protection officers, Richie, knocks on the bedroom door to wake me. Although I didn't go out last night, this is still fairly early for me. I normally get up at about 2pm if I've been to parties the night before. My left foot is still killing me. I fell down the stairs at Boujis the nightclub favoured by Princes William and Harry at the weekend and sprained it. It hurts like hell, but it's more of an inconvenience because it means I can't wear my new £500 Stella McCartney shoes. Instead, I opt for flip flops which I bought in Los Angeles. They're pink with little Swarovski crystals and cost £125 though I didn't realise how much they were until I reached the till. That often happens. I'd prefer to wear my heels, of course, but that's part of the price I have to pay for partying. 12 noon Suzie, my PA, comes over to go through some bills and post. I leave her to write the cheques and I just sign away. She earned my trust after only six months and now I can't imagine life without her. One of the downsides of being so wealthy is that I have been let down many times in the past with staff and so-called friends stealing clothes and items from my house. Now I find I can only really trust my family and my entourage: Suzie, my two housekeepers, my protection officers and two drivers. 1pm: I'm picked up to go to Christopher's Children's Hospice or CHASE in Guildford, Surrey. My husband Bruce and I have been Friends of the hospice for years and visit at least once a month. CHASE supports families with children who are so ill they are not expected to survive their teens. It is wholly supported by charitable donations which is where Bruce and I come in. It's a marvellous place and it makes me realise just how lucky I am to have this lifestyle. My friends and family are often saying I get complacent about my life, but that's a little unfair. I didn't always have this lifestyle. My grandparents were orphans who lived on the streets in Japan for a short while and my parents were struggling financially until I was about ten years old and my father made his money, so I do know the difference between rich and poor. Today, I'm helping the hospice organise a summer 'Jungle' party. We're planning a fashion show for the girls. I tend not to keep last season's fashions but give them away, so the children dress up and play princess. Bruce, who plays guitar and keyboard, does a musical day with the boys. 5pm: After leaving the hospice, I give shoe designer Jimmy Choo a call. We recently talked about creating an 'ethically friendly' range, but we need to sit down over lunch and discuss. He's in Malaysia on holiday so we'll meet up next month. It's very exciting. He's a lovely man and a fashion icon, and I'd love to be his muse. 8pm: I am a member of KX health club off Kings Road in Chelsea, so I pop in there for a steam room session to sort out my pores. Then I rush home to watch television. It's funny seeing people I've partied with on TV. George Best's son Calum chatted me up at a party just before he flew out to appear on the reality show Celebrity Love Island a few weeks ago. To be honest, I didn't even realise who he was at the time, but his chat-up lines made me cringe. He came up to me and said: "I predict you are going to be my future ex girlfriend." I thought: "No way." TUESDAY: 10.30am I have a private one-on-one boxing lesson with my instructor, Mati at KX. I really love these sessions and Bruce has just bought me pink diamanté boxing gloves for our fourth wedding anniversary. I'm always seeing Hugh Grant or Kylie at the gym. Today I bump into Tamara Beckwith, who tries to get me to join her at her 'spinning' class. Quite frankly, I can't think of anything worse. Instead, I suggest catching up with her later in the week. 2.30pm: Eeek, am late for a meeting with my photographer. We're arranging to do a glamorous photoshoot not for the Press, just for me and my husband. 3.30pm: I have a meeting with a production company about a possible show they want me to feature in. Bit nervous, but it sounds fun. On my way home, I call in at Stella McCartney's shop and pick up a couple of her new season £800 non-leather bags. Bruce and do I not wear any leather or animal-derived products. We drive hybrid cars and buy clothes online from vegan websites or Stella to avoid any leather. We are extremely ethically friendly. 7pm: Go for a meal and then drinks, where I bump into other friends just back from St Tropez and Ibiza. We all end up going to Boujis. The evening gets longer and longer and an I become rather tired and emotional. 2am: I decide the party isn't over and call up the Halkin Hotel in Belgravia to book their best suite so that everyone can carry on partying. It costs over £1,000, plus we get through 15 bottles of champagne, but we have a great night. WEDNESDAY: Noon Am dragged out of the Halkin Hotel, where I've been partying all morning, by my driver and protection p officer. The driver has been waiting for me since 7pm m last night and wants to go to bed. Get home and go straigh ht to bed myself - the joy of bei a rich socialite and not havin ng to work. 2pm: Ugh, the doorbell wakes me. It's our organic shopping being delivered and food for our dog Billy. Bruce and I are vegetarian but we realise that is not fair for Billy. Instead, we order organic chicken breast and the housekeeper cooks it for him daily with brown and white rice. He's quite fussy now and will eat only organic. He's never been left alone in his life and a dog-sitter needs to be booked when we both go out. He's a privileged dog and has been flown around the world on private jets from Tokyo to Hawaii, New York to LA, Paris to London. He takes after his mother. 5pm: I have to get up again because Stuart, my hairdresser, comes round to style my hair for an event tonight. He is one of the best celebrity hair stylists and does every-one's hair for the BAFTAs. He does Gillian Anderson, Alex Best and Tina O'Brien. He's also become a good friend because I love to gossip with him. I rarely make the effort to go to his salon now. There's no point when I can pay him £450 to come to me. 7pm: Sometimes I'd rather have a quiet night in with Bruce than go out, but if I'm invited I usually go. Bruce doesn't like parties and says he hates the superficial types you get there, but I enjoy mingling and meeting new people. Tonight, however, at the launch of a new club, none of my usual pals are there, so I stay for a couple of glasses of champagne and then move on to my members-only club, Annabel's in Berkeley Square. The usual wealthy girls, sugar daddies and high-profile people are there. I always have at least one of my protection officers to shadow me because some people know exactly how much I'm worth and I worry for my safety. But I don't allow my protection officers to socialise with me. They just to stand in the background and make me feel safe. 2am: Not really in the mood to carry on - I'd much rather have a massage. I like my massages at random times of the night when I've come in from a heavy dancing session. I have a great masseuse whom I can call any time, day or night, and she drops anything for me. So I wake her up and she comes over for a few hours. It's bliss. THURSDAY: 1pm Didn't get to sleep properly until about 8am after my massage, so I needed a lie-in. But I've got loads to do so I can't sleep in any more. Suzie comes round and helps me choose what to wear for the day. 4pm: We head to Stella McCartney's store, where I try on most of the dresses or anything from the latest collection. I've met Stella a few times and the staff in her store have come to know me well. They even allow Suzie to select items and bring them home to me. I return what I don't want and just pay for the ones I keep. 5pm: Bored. There's only so much shopping you can do and we decide to call it a day. End up going to another members-only club, Mortons in Berkeley Square, for a drink before I have to slip into evening attire.