Madonna Reuters

Pop diva Madonna has landed in controversy for using a racial slur in the caption of a photograph that she uploaded on photo-sharing website, Instagram.

The picture is of her son Rocco Ritchi boxing, and the proud mother praised her son's sparring prowess in the picture's caption which read, "No one messes with Dirty Soap! Mama said knock you out! #disn---a."

Soon, the 55-year-old was bombarded with complaints, with some pointing out that it was "uncool" to use a racial slur, even if the intention was not to hurt anyone.

"Martin Luther King Jr. did not die for this..." Instagram user mrchristiancage wrote objecting Madonna's caption.

The "Material Girl" immediately removed the photograph, only to upload it later with another message that read, "Ok let me start this again#get off my d--k haters!"

She even apologized for using the N-word and said that it was not meant as a racial slur.

"I am sorry if I offended anyone with my use of the N-word on Instagram," the singer said in a statement to E!News. "It was not meant as a racial slur...I am not a racist."

She added, "There's no way to defend the use of the word. It was all about intention...It was used as a term of endearment toward my son who is white.  I appreciate that it's a provocative word and I apologize if it gave people the wrong impression. Forgive me."

Rocco, 13, is Madonna's only son with director ex-husband Guy Ritchie. She has a 17-year-old daughter, Lourdes, with Cuban actor Carlos Leon, and has two adopted children - Mercy and David, both eight, from Malawi.

Interestingly, this is not the first time Madonna has landed in trouble for uploading something that online users found offensive. Welcoming the new year, Madonna posted a picture of her son and two of his friends holding liquor bottles, which had critics questioning Madonna's parenting capabilities.

"No one was drinking we were just having fun! Calm down and get a sense of humor!" she responded to critics. "Don't start the year off with judgement!"

The photograph was taken in Switzerland, where the legal drinking age is 16.