Not Jeb, the former Florida governor and Cruz's former primary opponent, or George W., the 43rd president who has had a frosty relationship with the Texas senator -- but Neil, a younger brother of both. A prominent Houston businessman, Neil Bush joined Cruz's fundraising team along with his wife, Maria.

Cruz, who has long been one of the top fundraisers in the crowded GOP field, added 13 new bundlers who will help him raise the cash to compete with Donald Trump, who is largely self-funding his campaign. Also joining as new Cruz fundraisers are Don Huffines, a Texas state senator formerly backing Rand Paul, and Dick Weekley, a Republican powerbroker in Texas politics.

Cruz's campaign said on Tuesday it had now raised more than $70 million over the course of the campaign.

In the past, Cruz has had a fraught relationship with the Bush clan. Cruz worked on George W. Bush's 2000 presidential campaign, but since then he has largely charted his own course in Texas politics. He has been critical of George W. Bush's presidency on the campaign trail, and the former president returned the favor by telling a private audience in October that he just does "not like that guy."