Apple CEO Tim Cook gave a commencement speech at George Washington University in which Cook spoke about Martin Luther King Jr, working with Steve Jobs, and meeting president Jimmy Carter.
But Cook couldn't resist making a little joke aimed at the people who were using Android phones in the audience.
"They've asked me to make a standard announcement ... about silencing your phones," Cook said. "So those of you with an iPhone, just place it in silent mode. If you don't have an iPhone, please pass it to the centre aisle; Apple has a world-class recycling programme."
That wasn't the first time that Cook has joked about competing smartphones. He told attendees at the company's 2014 WWDC conference that 130 million Apple customers who bought one of the company's products in the past 12 months were first-time Apple buyers.
He said that, "Many of these customers were switchers from Android," and also said "They had bought an Android phone, by mistake, and then sought a better experience. And a better life. And decided to check out iPhone and iOS."