Jennifer Lopez and Alex Rodriguez Made It Rain On Strippers For Research

Here's A-Rod talking about how he and J Lo have gone to multiple strip clubs together and spent thousands on dancers ... but he SWEARS it had nothing to do with getting freaky.

It was all for "research" ... and Alex says it was the BEST work he's ever done!

Of course, Lopez is starring in the upcoming stripper flick "Hustlers" -- and Alex told the guys on "The Breakfast Club" he was more than happy to help Jen get ready for the role.

"I was out in L.A. She's in New York. She says, 'Baby, I'm going to the strip club.' I said, 'WHOA!! I'll be there on Thursday. We can go Thursday and Friday,'" Alex said.

"I mean, it's part of due diligence, right?"

Alex says Lopez was a total pro -- and tried to learn everything she could about dancers ... but Alex says he's kind of an expert when it comes to the booty club.

"She read and read and read [about strippers] ... I said, 'Baby, stop reading and just ask me. I got the info!'"

Alex says he almost knew "too much" about the stripper world -- "which was kind of scary."

Inside the clubs, Alex says the couple would pay THOUSANDS to women ... not to dance, but to talk.

"We sat down with the girls, and we literally just interrogate them, ask them questions. Then, we would hit 'em up with $400 or $500 or $600. We weren't there for dancing, we were literally there for work."