(CNN) Former British Prime Minister David Cameron joked Monday that "I don't have to listen anymore to the wiretaps of Donald Trump's conversations" now that he's out of office -- quickly adding, "that's a joke," as he winked at the controversy roiling American politics.

Cameron spoke at Brown University for the 94th Ogden memorial lecture on international affairs, according to a report from the Guardian, and discussed a variety of topics that included Russian President Vladimir Putin and the Trump administration's unfounded accusation that the British spy agency GCHQ helped former President Barack Obama surveil Trump's 2016 presidential campaign.

Last week, White House press secretary Sean Spicer cited an uncorroborated Fox News report to allege that the UK intelligence agency spied on Trump at the behest of Obama.

The claim -- called "ridiculous" by a spokesman for Prime Minister Theresa May -- resulted in what amounted to an apology from Spicer and national security adviser H.R. McMaster to the British government, a senior administration official told CNN, though Spicer later denied an apology had taken place.

On Monday, FBI Director James Comey told Congress he was not aware of any evidence to support Trump's claim that he was wiretapped by Obama during the campaign.

Cameron also made a joking reference to the viral photo of Putin riding horseback shirtless.

"I'm very fond of riding horses, but I don't look quite the same with my shirt off," he said, according the report.

The former British leader struck a more serious tone in other remarks, weighing in on globalization and Britain's vote to leave the European Union.

"When the Berlin Wall fell in 1989, it felt a bit like all the big arguments were over. It was obvious that we needed more democracies, we needed more rule of law, we needed free enterprise, we needed free trade, we needed NATO, we needed to stand up to aggression, we should invest in the United Nations -- today, all of these questions are under debate," Cameron said, according to the Guardian.

Playing on Trump's campaign slogan, Cameron added that "we really will be great again" if the US and UK continue to fight for their values.