Sir Roger Bannister, the first man to run a mile in under four minutes, cheered on schoolchildrenas they hit the ground running for Sport Relief.
The 80-year-old former athlete offered words of encouragement to youngsters at an east London track as they donned their trainers and red T-shirts for the charity appeal.
About 190 children from Our Lady Catholic Primary School in Limehouse raced against each other, with some as young as eight managing to complete a full mile.
Perched on a chair by the side of the track at Mile End Stadium, Sir Roger - whose grand-daughter is a teacher at the school - said it is "enormously important" for children to be encouraged to participate in sports.
"One of the reasons why we have fallen behind in athletics is because there has been not enough support in schools," he said.
"Playing fields have been sold off and the number of opportunities has gradually decreased."
The former Olympian, who kicked off his athletics career at an elementary school in west Harrow, said he was "delighted" to see the youngsters enjoying their sprint round the track.
"I am glad that they have the opportunity to take part today and to get the experience of what a track looks like," he said.
"It's wonderful to hear them excited, wanting to do their best.
"Sport, I have always thought, is very important to be introduced at an early as possible age and that's what they are trying to do here."
One runner, Erin Small, seven, who completed half a mile, said: "It was fun - I was excited to come and run around the track."
Shakeen Giwa, eight, said he was "pleased" to have run a full mile.
"I came to the track two weeks ago and I have been practising," he said.
Though no one managed to match Sir Roger's record on the track, they raised more than £400 for Sport Relief.
Headteacher Andrew Rafferty said: "They were really pushing themselves to get around and they were wanting to impress Sir Roger who has been a fantastic influence.
"Their enthusiasm at the end of the day is great. Sport is an important part of their education for life."
A series of Sport Relief programmes kicks off on BBC1 at 7pm on Friday.
The evening will include a host of one-off specials, including Ashes To Ashes, Mock The Week, Question Of Sport Relief and MasterChef.
There will also be musical performances from the likes of Robbie Williams and JLS and the first UK TV appearance from Cheryl Cole since she announced she was splitting from husband Ashley.
Recent sporting challenges by Eddie Izzard, Helen Skelton, Christine Bleakley, Lawrence Dallaglio and celebrity cyclists led by David Walliams will also be screened.
Meanwhile figures such as Daley Thompson and Jonathan Edwards are among well-known athletes teaming up with TV's The Choir guru Gareth Malone.
They will be showing off their skills with a choral rendition of Elvis Presley's classic Always On My Mind when they appear live, along with Roger Black, Jamie Baulch and Iwan Thomas.
Sport Relief bosses said this would be Malone's biggest challenge yet.
The TV spectacular aims to raise millions for charity, and tens of thousands of people around the UK will rise to the challenge for the Sport Relief Mile on Sunday in which volunteers will take part in a sponsored run.
© Press Association