You might remember that more than 500,000 people have joined a Facebook event to storm the classified US base in order to see what they've got hidden away in there. According to Lazar, that wouldn't be a great idea.
In fact, he claims that the last bloke who tried to do it was shot dead. The US military have got some pretty big guns, remember?
Lazar took to Instagram to offer some friendly advice to the 'Storm Area 51' crowd.
He said: "I have to comment on this 'Storm Area 51' thing. I do understand it was started as a joke by someone, but there are a number of people who are actually planning on showing up.
"This is a misguided idea. Area 51 is a classified research base. There are no aliens or alien technology located there.
"The only place there was ever any alien technology was at Site S4, south of Area 51 proper. That was 30 years ago.
"S4 may have moved decades ago or it's possible it's no longer being used for the project. I do not support this 'movement'.
"The last time someone tried to get in to Area 51 he was shot. This is not the way to go about trying to get more information.
"What is good, is the interest in the subject - the science and technology. That is what would immediately change the world we live in."
OK Bob, whatever you say.
So, if Area 51 isn't where they are keeping the saucer people, what exactly is this 'Site S4' of which he speaks?
Well, according to Lazar, it was an even more secret base made up of aircraft hangars built into the mountainside south of Area 51.
Lazar claims that he was employed to reverse-engineer technology that was discovered by the US and taken to this top secret off-the-grid site.
He's a pretty interesting guy, to be fair.
Lazar claims that he has seen documents detailing alien activity on Earth that has been going on for a while. However, it is worth remembering that the scientific community is sceptical of his work, given that he presents his claims with little hard evidence.
One thing he says is definitely true, though. It's not a great idea to try to storm military bases.