"Rest in Power:" Celebrities react to the death of Sinéad O'Connor

As news broke Wednesday about the death of Irish singer Sinéad O'Connor at the age of 56, many around the world took to social media to share tributes to the artist arguably best known for her cover of the Prince song "Nothing Compares 2 U."

O'Connor overcame a difficult childhood, achieving her first major musical success in the late 1980s for her debut album "The Lion and the Cobra." But it was her second album, "I Do Not Want What I Haven't Got," which made her a household name. She earned one Grammy win and eight nominations, and was named Rolling Stone artist of the year in 1991. 

Along with her music, O'Connor was known for her outspoken stance on political and social issues, and was open about her struggles with mental health. Stars across the world Wednesday remembered and celebrated the singer for her fiery spirit.