"She is way out of his league. If he wants to get in a character fight he should stick with me," Cruz told ABC News’ George Stephanopoulos in an interview on "Good Morning America" today.
"You know I guess he’s used to dealing with people that he can just bully and threaten and intimidate and they run away, and I got to say the fact that he comes after Heidi, reveals a lot about character," Cruz said.
Cruz went on to argue that Trump threatened Cruz and his wife because he lost yesterday's Utah Republican caucuses to Cruz.
Trump threatened Cruz Tuesday after the anti-Trump super PAC, Make America Awesome, released an attack ad featuring a racy image of the billionaire's wife, Melania, from her former modeling days.
Lyin' Ted Cruz just used a picture of Melania from a G.Q. shoot in his ad. Be careful, Lyin' Ted, or I will spill the beans on your wife!— Donald J. Trump (@realDonaldTrump) March 23, 2016
Wednesday, Heidi Cruz responded to Trump during an impromptu press availability outside the Cruz campaign office in Waukesha, Wisconsin.
“You probably know by now that most of the things Donald Trump says have no basis in reality," Mrs. Cruz said. "So we are not worried in the least. We’re focusing on our campaign. We're going to continue to do that."
Heidi Cruz also skirted around a question from a reporter asking if candidate’s spouses are fair game during a campaign.
"We have run our campaign with the principles that Ted and I believe in," Mrs. Cruz said. "And a lot of the things that are done from time to time are not from our campaign, and so I want you to focus on what our campaign puts out, which you'll find is a positive, hopeful, optimistic agenda for this country."
In his interview on "Good Morning America" Wednesday morning, Cruz also defended his controversial call to empower law enforcement to patrol Muslim neighborhoods following Tuesday's terror attacks in Belgium.
"Yesterday reminded everyone that we are facing a war from radical Islamic terrorism. President Obama, Hillary Clinton, they refuse to acknowledge, they refuse even to say the words radical Islamic terrorism," Cruz said.
When pressed on whether targeting Muslim neighborhoods was constitutional, Cruz said, “What we should [be] targeting is radical Islamic terrorism and the political correctness of this administration.
"They refuse to acknowledge that we are facing a global jihad from radical Islamic terrorism. And indeed after just about after every one of these attacks, whether Paris or San Bernardino and certainly coming after Brussels, President Obama goes on national television and lectures Americans on Islamophobia. Enough is enough."
ABC News' Lissette Rodriguez contributed to this report.