PHOENIX - Republican presidential nominee Donald Trump will be making his seventh campaign stop in the Valley on Saturday, according to campaign sources and Trump's son.

Donald Trump Jr. announced his father was heading to Phoenix at the tail end of a rally Thursday at Arizona State University in Tempe.

"I heard my father's coming back to Phoenix on Saturday," he said, closing his speech.

Trump's need to make his second campaign trip to Arizona in less than four weeks -- he was in Prescott Valley Oct. 4 -- highlights one of the more surprising stories of this presidential election: Reliably Republican Arizona is up for grabs between Trump and Democrat Hillary Clinton.

The rally will take place at the Phoenix Convention Center.

Doors are scheduled to open around noon with his speech starting later in the day.

Tickets are free but you can only get two per mobile number.

The Arizona Capitol had been considered as a venue, but has been ruled out, 12 News has learned.