SAN ANTONIO -- San Antonio City Councilman Julian Castro and State Rep. Joaquin Castro both denied allegations that they tried to dupe the public Monday night when the state lawmaker rode on a City Council float instead of his twin brother.

Julian Castro, who is running for mayor, attended a candidates forum and was not able to attend the Texas Cavaliers River Parade. Instead, he sent his brother, who was announced to the public as Julian Castro.

Joaquin Castro could be seen waving to tens of thousands of parade goers.

The Castro twins blame the parade announcer for the mistake and denied they intentionally tried to mislead voters.

"I don't know if they want me to hide at the bottom of the boat or not raise my hand and say hi to anybody," Joaquin Castro said Thursday at a news conference flanked by his twin brother. "But I said hi to folks. Ninety percent of people know there are two of us."

The twins are laughing off the incident and wore T-shirts at the news conference that said, "I am Julian" and "I am not Julian."

But Julian Castro's mayoral opponents don't find the incident funny.

Councilman Carroll Schubert, who was standing next to Joaquin Castro on the float, said, "I just don't do that, that's not the way I operate."

Former Judge Phil Hardberger said, "To pretend someone else is you is a question of credibility."

Joaquin Castro said his opponents need to concentrate on the "real issues" and forget about the incident.

It's not the first time the twins have been accused of impersonating one another.

Julian Castro was accused of impersonating his twin brother when Joaquin Castro ran for state representative.