Daniel Wallace was only 11 years old when Michael Phelps won his first gold at the 2004 Olympic games in Athens.
So you can probably imagine the 23-year-old Scot swimmer grew up wanting to be like more like Phelps, who how has 21 Olympic golds with possibly more coming his way.
So when Wallace watched the 31-year-old US swimmer walk past him - in his blue robe and wearing headphones - just before diving in for his 200m individual medley semi-final, he couldn't help but show his admiration for one of the swimming greats of all time.
We aren't surprised - it seems a pretty natural reaction to someone who has been worshipped by sports fans round the world.
Wallace made it to the final and Phelps was fastest qualifier in the event.
Phelps has won the 200m individual medley in the past three Olympic games, so Wallace has some tough competition ahead of him.