Donald Trump’s embrace of Brexit, the United Kingdom’s vote to leave the European Union, just reached new heights: His rally in Jackson, Mississippi, tonight will feature an appearance from Nigel Farage, the British politician and former UK Independence Party leader who boosted the pro-Brexit campaign.

A right-wing British politician with little name recognition in the US might seem an unusual guest at a campaign rally for the White House. But in the two months since Britain voted to leave the EU, Farage has become a hero to some Trump supporters within the conservative movement. Trump himself has hailed the vote as Britain taking “their country back.”

The Brexit campaign has become an analogy and a cautionary tale about Trump’s run for the White House.

Farage isn’t expected to endorse Trump at the rally, according to the Guardian. But his appearance is the latest evidence that Trump is embracing the comparison between his campaign and the Brexit vote, a decision motivated by fears of immigration that seems likely to be economically and politically chaotic for the United Kingdom.

How the Brexit campaign became a metaphor for Trump

When the United Kingdom voted to leave the European Union on June 23, the comparisons to Trump’s campaign were immediate and obvious. Brexit, like Trump, was supported by older voters outside of urban areas who feared the influence immigrants were having on their country. And they triumphed.

On the American left, this quickly became a cautionary tale: If a seemingly unthinkable Brexit could really happen, so could a seemingly unthinkable Trump presidency. This is actually a fairly weak analogy — the UK and the US are demographically different, a referendum is less personality-driven than a presidential campaign, and the polls had long indicated that a Brexit was within the realm of possibility — but it became a rallying cry to take Trump seriously.

And it’s become increasingly obvious that Trump finds this to be a compelling analogy as well. Last week, he tweeted this:

They will soon be calling me MR. BREXIT! — Donald J. Trump (@realDonaldTrump) August 18, 2016

Like many Trump tweets, the exact meaning is a bit opaque. But Trump is clearly eager to embrace the success of the Brexit campaign and apply it to his own. Trump is also tapping into some of the same anti-immigrant sentiments that have propelled the rise of far-right parties in Europe, including the UK Independence Party, which Farage led until recently.

Trump didn’t publicly give much attention to Brexit during the run up to the vote, but one of the most pro-Brexit outlets in the American media was the conservative Breitbart News. After the vote, Farage thanked Steve Bannon, Breitbart News’s executive chairman, for being fair and giving him “a chance to make my arguments.”

Bannon is now the leader of Trump’s presidential campaign. In that light, Trump’s sudden fondness for Brexit makes a lot of sense. Why not invite its face to your campaign rally?