The pair did so literally on Wednesday as they rallied opposition to the Iran nuclear deal that just a day earlier secured enough Senate support to kill Republican efforts to derail the deal.
"It is a bit of a romance," Trump told CNN at the rally. "I like him, he likes me. He's backed me 100% about illegal immigration. He was the one person that really -- and there were a couple of others -- but Ted Cruz was out there and he backed me very strongly."
But that's about as far as Trump would go. Asked whether he would encourage his supporters to back Cruz should he drop out, Trump still sounded like the Republican front-runner.
"I'm not dropping out of anything, I never drop out," he said, addressing dozens of reporters behind the stage at the same time as Cruz addressed the crowd gathered below the steps of the Capitol.
While Trump stole some of the spotlight from Cruz, the Texas senator admitted the businessman's star power was part of the appeal.
"The reason's not complicated," Cruz told reporters Thursday outside a tea party rally. "No. 1: I like Donald. He's a friend of mine. But when Donald arrives at an event, he brings an army of TV reporters. And Donald's being there ... means the mainstream media will cover the event."
The Cruz-Trump bromance was hatched in the opening days after Trump's controversial launch speech when the senator was one of the few in his party to refuse criticizing the businessman. It's one of the more surprising subplots of a summer dominated by who Trump was sparring with on any given week.
The alliance makes for good politics, and Cruz is hoping to inherit Trump's supporters should the bombastic businessman fall, aides have said. Trump is hoping for the same.
For Trump, the benefits are less obvious. He doesn't need Cruz to draw media attention or a crowd. Yet the rally will play to his strengths as a fierce critic of Obama's foreign policy and a tough negotiator who would cut deals to restore U.S. status in the world, said Roger Stone, a former Trump political adviser.
As for how long Trump and Cruz can maintain what appears to be a nonaggression pact, Stone said it's too early to tell.
"We don't know if Cruz will ever get any traction," Stone said.
While Cruz reveled in the media attention that only the billionaire businessman can attract, the event gave Trump a chance to redeem himself after stumbling over a series of foreign policy questions. Ultimately, though, the rally was as much about their unusual alliance as it was about scuttling the Iran nuclear deal, which appears to be increasingly safe from Republican efforts to sink it on the Hill.
"I don't anticipate that rally will have any impact on the ultimate vote in either the House or the Senate," Republican Sen. Susan Collins of Maine told CNN Tuesday moments after declaring her opposition to the Iran deal.
That's besides the point, says Republican strategist Ron Bonjean.
"It's not going to change what's going on in Washington right now, but they're scoring political points," Bonjean said.
The event culled speakers from a who's-who roster of conservative icons: Talk radio hosts Mark Levin and Glenn Beck, former Alaska Gov. Sarah Palin and Duck Dynasty star Phil Robertson.
Rep. Dave Brat of Virginia, who carried tea party support to oust former House Majority Leader Eric Cantor last year, rallied the crowd before the presidential contenders with talk of the Republican establishment's failings.
But as Cruz himself recognized, the rally took on new explosiveness when Trump told an audience two weeks ago that he would lend his star power to the event. Trump's attendance was news to Tea Party Patriots head Jenny Beth Martin, who is organizing the rally. Martin explained that she eventually invited all other GOP presidential candidates on Friday -- well after organizers unveiled the duo as headliners.
Cruz's Iran play comes ahead of a congressional season where the freshman senator is set to play a lead role in the fight to defund Planned Parenthood, even at the risk of shutting down the government at the end of the month -- which GOP leadership wants to avoid. Cruz, of course, was a key figure in forcing a government shutdown in 2013 over Obamacare.