A group, including Parkland, Florida, shooting survivor David Hogg, said they have raised enough money to display a billboard showing old tweets from President Trump criticizing Cruz.
In a tweet on Friday, the president said he would rally for Cruz in October somewhere in Texas.
Cruz is facing a challenge from Democrat Beto O'Rourke, who is mounting an aggressive campaign and raising a significant amount of money in his bid to unseat the conservative senator.
President Trump to stump for Ted Cruz in Texas