Madonna fires off musical dig at Lady Gaga with 'Born this Way' cover Stephen Lovekin / Getty Images Madonna wanted to express herself, all right. But was it to give props or poke fun? The pop superstar was caught on video this past weekend in Israel rehearsing for her upcoming world tour when, mid-song, she suddenly burst into a Lady Gaga ditty and melded Mama Monster's lyrics with Madge's own. Shall we ring the bell for round two (or three) of Madge's ongoing feud with Gaga? And what were the songs in question? MORE: So what does Madonna really think of Lady Gaga's "Born This Way?" Hint: Not much But of course: It's "Express Yourself" versus "Born This Way." In the footage, which was apparently shot on the DL by a snoopy onlooker privy to the rehearsal (security clampdown!), Madge bops and belts her 1989 female-empowerment hit. Suddenly, after the breakdown, she bursts into Gaga's "Born This Way," ping-ponging back and forth between Gaga's own 2011 female-empowerment hit and "Express Yourself." PHOTOS: Fashion spotlight -- Lady Gaga Natch, the mash-up works impeccably, bolstering Madge's previous snarky comments that Gaga ripped off her song -- and her style. "I certainly think she references me a lot in her work," the 53-year-old pop diva told 20/20 in January. And sometimes I think it's amusing and flattering and well done. There's a lot of ways to look at it. I can't really be annoyed by it ... because, obviously, I've influenced her. MORE: Lady Gaga cancels Indonesia concert amid protests That's certainly something that Gaga hasn't tried to hide: She's often cited Madonna as a major inspiration to her music. Madge later snickered, "When I heard ("Born This Way") on the radio.... I said that sounds very familiar. It feels reductive. Gaga, of course, now finds herself in a predicament reminiscent of Madonna's Catholic-skewering heyday after being forced to cancel her show in Indonesia following massive protests over her racy persona. Perhaps Gaga might want to return Madonna's, um, homage and cover one of Madge's songs at an upcoming concert. May we suggest "Justify My Love"? Who's your favorite wild siren -- Madonna or Lady Gaga?