MAMA Monster has declined an invitation to perform with the Material Girl, according to Billboard.

It's been a less than stellar year for diva-diva relations, especially between Madonna and Lady Gaga, who have spent the last 12 months trading snipes at one another at various concert stops around the globe.

In her MDNA tour, Madonna includes a snippet of Gaga's Born This Way in her rendition of Express Yourself — a heavy wink at the similarity between the two songs. This after Madonna told an ABC interviewer last January that the Gaga composition sounded both familiar and "reductive."

But at a recent tour stop in St Paul, Minn., Madonna says she holds no grudges against the next-generation pop star, and had even asked her to join her for a duet, according to The Huffington Post.

"I have the best fans in the whole world. So take that, Lady Gaga!" Madonna told the crowd. "You know, I invited her onstage to sing with me. But, she turned me down. It's okay. I've been rejected before. It builds a little character."

Madonna's last North American tour stop is Nov 20 in Miami, then she takes off for the South American leg of her tour.