You may have heard of Eric Schmidt — he's the executive chairman of Alphabet, the parent company of Google that makes the Android mobile operating system.

But Schmidt has admitted that he uses an iPhone 6s — made by rival Apple.

During a "fireside chat" with CNBC at Startup Fest in Amsterdam on Tuesday, Schmidt said he was an iPhone user, but also has a Samsung Galaxy S7, which runs Android.

And guess which one he prefers.

"Samsung S7 is better. It has a better battery. And those of you who are iPhone users (know) I'm right," Schmidt said.