Madonna Covers Lady Gaga's 'Born This Way' During Rehearsal

Pop icon Madonn

a may have fired another salvo in the ongoing musical feud between her and Mother Monster Lady Gaga.

The Material Girl reportedly may be using her upcoming concert tour as a forum to perform a Material Girl/Mother Monster mash-up.

During a recent concert rehearsal in Israel,  Madonna was caught on video performing her 1989 composition, "Express Yourself," before transitioning into Lady Gaga's "Born This Way," complete with the sound of a revving motorcycle that is Gaga's trademark.

Madonna seamlessly flipped back and forth between the choruses of both songs to further illustrate the similarities.  She ended with a drum-driven remix of "Express Yourself" and chanted chorus of "Respect yourself … she's not me."

Whether it was an homage or a pointed dig went unstated, but Madonna told "Nightline" anchor Cynthia McFadden in a January interview that  Lady Gaga's hit song "Born This Way"  felt "reductive" of "Express Yourself."

Watch: Lady Gaga talks about faith and family, and sings "Marry the Night."

Lady Gaga has made her mark with a unique style of dress and music that many say is reminiscent of  Madonna's iconic style and attitude.

And it's no secret that the "Poker Face" singer admires Madonna; she has spoken of her regard for the pop icon. But  the admiration apparently is not mutual.

Last year when a Belgian magazine's reporter asked Madonna about her fans, including Lady Gaga, the singer replied, according to the magazine:  "I have no comment on her obsessions related to me, because I do not know if it is based on something profound or superficial."