Is vomiting onstage the next hot, new pop star trend?

--Over the weekend, LADY GAGA threw up while performing "Edge of Glory" in Barcelona . . . just one week after JUSTIN BIEBER barfed in the middle of a song during a show in Arizona. 

(--He later blamed it on a heavy meal of spaghetti bolognese and milk.)

--In the middle of the song, Lady Gaga turned her back to the crowd and went at it, while some unlucky dancer covered her by doing his thing right in front of her.

--"Sources" say she'd been battling the flu, but didn't want to cancel the show.

--Gaga hasn't commented on what was wrong . . . but she did have some fun with it on Twitter.  She said, quote, "Was praying nobody saw but actually it's quite a good laugh if you need one!  Check out Lady PukeGA doing Swan 'Vomit' Lake."

(--Here's the video.  WARNING:  You can actually see her vomiting, so keep that in mind if you don't think you have the stomach for that this morning.)

--Unlike Justin, Lady Gaga didn't leave the stage . . . technically . . . and powered through, even after throwing up three times.  She DID disappear behind a prop for 30 seconds though, presumably to clean herself up.

--That's totally understandable . . . considering how closely she was interacting with one of her dancers when she returned to the stage.  He lifted her, carried her around, and their mouths got so close, their LIPS MAY HAVE TOUCHED.

(--You can see that in this longer video.)