The Heart Attack hitmaker stepped in last week (begs06Jul15) to replace Grande as the headliner at the Major League Baseball All-Star Game Concert as the Problem singer faced a backlash over a recent visit to a bakery in Lake Elsinore, California, where she was filmed appearing to lick doughnuts on the store counter and declaring, "I hate America".

Florida native Grande, who blamed the show cancellation on her recovery from dental surgery, has since apologised for her statements, insisting she was simply expressing her frustration with America's obesity issues.

Now Lovato has found herself under fire for including her patriotic song Made in the USA in her MLB All-Star Game Concert set, during which she told the crowd, "I know it's a little late, but I didn't get to sing this on the Fourth of July... How many of you are proud to be an American?"

Some people interpreted the comment as a cheap shot at Grande and criticised Lovato on, prompting the star to hit back and deny the allegations.

Responding to the detractors, Lovato writes, "Didn't get to sing Made in the USA on the 4th because I was singing (her new single) #COOLFORTHESUMMER. No shade - stop the bulls**t".

She adds, "ALSO - I ALWAYS ask that when I sing that song. Can't yall (sic) let a girl shine for one night? Smh (shaking my head)."