Tom Daley says lemon juice helps him stay in shape.
The 21-year-old Olympic diver is known for his muscular, yet lithe, physique, and has been sharing his diet and fitness tips in a series of video blogs.
His latest message explains the benefits of having a glass of lukewarm lemon water every morning.
He says: "The first thing I do every single morning is have a glass of lemon water. It's quick, it's easy and it's simple. It makes me feel good, it gives me energy, it's great for weight management and I think it tricks my body into thinking I'm going to have plenty to eat and drink throughout the day, so my body doesn't hold on to anything that it doesn't need to."
While many people have lemon juice with ice cold water, Tom insists it's better to have the water slightly warm.
He added: "The one top tip that I would give everyone is to keep the lemons and a glass in your bathroom and so every time you wake up the first thing you do is squeeze the lemon juice into your glass - Bob's your uncle, fanny's your aunt - and you've got some lemon water. Preferably use lukewarm water because then your body metabolises it a little bit quicker."
Tom then lists the benefits of lemon juice, including boosting the immune system, aiding weight loss, helping the skin, boosting energy and staving off hunger cravings.