Barcelona ace Leo Messi has lifted the lid on why he didn't sign for River Plate as a junior.

The story of Messi's trial with River is well-known, but this is the first time he has talked about the details of the situation.

"I went to River because one of my teammates went to Buenos Aires to try out," Messi told Fox Sports in Argentina.

"I played 20 minutes and scored four goals and they told me to come back with a permit.

"They wanted to pay for my hormone treatment, something that they didn't do at Newell's Old Boys.

"But when I went to look for the permit [at Newell's Old Boys] they never gave it to me.

"Then later I went to Barcelona."