Edwin Moses told Special Report Britain's Olympic athletes can be inspired by their home support - but says it's not guaranteed to bring glory.
With the Games being held in London there are hopes home advantage will play a part and boost the performances of Team GB athletes.
Moses knows what it's like to perform in front of a home crowd at an Olympics after bagging gold in the 400m hurdles in Los Angeles in 1984 and he says the support can affect people in different ways.
"Home advantage can cut both ways," he said. "If you're a star and you have lots of obligations - family to see, press to speak to, sponsors to meet - that can all distract from what you're doing.
"Home advantage really can lift you but if you're out there and you're waiting to see what will happen and thinking your boost of energy is going to come from the crowd then you may come up short.
"Unfortunately you don't know how you'll react. The first indication you'll get is when you walk into the stadium for the opening ceremony and the hairs on your back stand up and you get chills across your body."
Sally Gunnell is confident the home support will inspire Britain's athletes to reach their track and field target of eight medals - which is four more than they achieved in Beijing.
"I think it's possible," she said. "Realistically if we can get two golds we will have done well, too.
"Competing at home is an advantage but it's where the athletes put that in their mind that's important.
"They have to use it and think: 'I''ve got everyone in that stadium, everyone in the country, cheering me on, wanting me to win."