While the rest of the world celebrates Jennifer Lopez and Alex Rodriguez's engagement, former New York Yankees star Jose Canseco has accused A. Rod of cheating on J. Lo with his ex-wife.

On Sunday (Mar. 10), just one day after the couple announced their engagement via Instagram, Canseco took to Twitter to claim—without any evidence—that Rodriguez is cheating on his new fiancée with Jessica Canseco. He called Rodriguez a "piece of sh-t" and alleges he was there when Rodiguez called her a few months ago.

"Watching World of Dance watching J.Lo text Alex Rodriguez little does she know that he is cheating on her with my ex-wife Jessica poor girl she has no idea who he really is," Canseco began his rant, before writing, "I was there a few months back with her when he called her on her phone"

"Alex Rodriguez, stop being a piece of sh-t stop cheating on Jennifer Lopez," Canseco added, before challenging Rodriguez to a boxing match. The former New York Yankee even went as far as saying he'll take a lie detector test to prove Rodriguez is being unfaithful and that what he's saying is "100% accurate."

Neither Lopez nor Rodriguez have responded to Canseco’s accusations and neither has posted on their social media since their engagement news.