Joseph Schooling of Singapore was a 10-year-old when he first met Michael Phelps. When he was around 13 in 2008, he took this picture with his idol:

According to NBC's broadcast Thursday, Schooling's father asked Phelps for advice on where to send his promising son for swimming training. He ended up at Bolles, a boarding school in Jacksonville that has produced gold medalists Trina Jackson, David Larson, Martin López-Zubero, Anthony Nesty, Fred Tyler, Ashley Whitney, Caeleb Dressel and Ryan Murphy.

Dressel and Murphy, U.S. gold medalists in Rio, were Bolles classmates with Schooling, who swam collegiately at Texas. At the 2015 world championships, Schooling won a bronze in the 100-meter butterfly. That's the Olympic event in which Phelps has won three straight gold medals and holds the Olympic and world records.

Competing next to Phelps on Thursday in a 100 butterfly heat in Rio, Schooling swam a 51.41. Pulling up behind him was Phelps at 51.60. Schooling's time was the best of the six heats, while Phelps was fourth.

The race made for a good photo opportunity of the two swimmers.

Schooling, 21, has grown up. And that could be bad news for Phelps. The two-time Olympian and long-time Phelps fan has a chance to dethrone his idol in one of Phelps' most reliable events. Both advanced to the semifinals later Thursday. The final is Friday night.

More Phelps:

-- Michael Phelps' 20th Gold Medal Is His Most Emotional

-- These Pics With Michael Phelps, His Mom And His Son Are Priceless

-- Why Did Michael Phelps Laugh During National Anthem? Blame The Orioles

-- Follow Jeffrey Eisenband on Twitter @JeffEisenband.