The couple met while playing lovers in the promo for the singer's 2011 single You and I, and began dating soon afterwards.
Gaga has now revealed she knew romance was in the air when Kinney stole a kiss from her on set.
In an interview with U.S. talk show host Ellen DeGeneres, which will air on Monday (25Nov13), she says, "He's a hidden weirdo. He is extremely strange, actually, and we complement each other's weirdness... That's actually one of the first things he ever said to me. It's a Dr. Seuss quote that you find in someone else a compatible weirdness...
"The first time he met me it was on the set of the You and I video... (I was looking) ridiculously crazy... I've got these pins sticking out of my head and I'm wearing cork and I got no hair and I'm bald. And I mean, why he found me attractive just completely behooves (sic) me. And we were in the middle of this scene and I remember that he kissed me and it wasn't scripted for him to kiss me and I was sort of like, 'Um, you know, was that real or was that fake?' And he didn't really say anything and that was fine by me and we kept filming. And you know, at the end of the day he's my best friend and having your lover be your best friend. I mean, it's the best thing ever. It's the best thing I can say about it."
She adds of her relationship with the actor, "We're boys. I wear his flannels, we eat pizza, we watch Tv and then I play him my next single and ask him if he likes it. And that's our normal life."