Sharon Stone has responded to Madonna's description of her as a ''mediocre'' actress by insisting she only has ''love'' and admiration for the pop star.

The 58-year-old singer detailed her frustration that Stone and Whitney Houston had both enjoyed more successful careers in the music industry and in Hollywood than her in a private letter which she penned in the 90s and is being auctioned off next week.

In the note - which was written to actor John Enos - the 'Like a Virgin' hitmaker said: ''It's so unequivocally frustrating to read that Whitney Houston has the music career I wish I had and Sharon Stone has the film career I'll never have.

''Not because I want to be these women - because I'd rather die, but they're so horribly mediocre and they're always being held up as paragons of virtue [or] some sort of measuring stick to humiliate me. (sic)''

Stone, 59, has posted an open letter on Facebook addressed to Madonna in which she insists she is not angry with the singer for the comments, which she made in a private letter, and insists she is still her dear ''friend''.

Her post read: ''Dear Madonna, First, I think it's absurd that anyone is publishing your private letters. Therefore; I publish publicly. Know that I am your friend. I have wished to be a rock star in some private moments ... have felt as mediocre as you described. We know, as only those who have survived so long that owning our own mediocrity is the only way to own our own strengths; to become all that we both have become. I love and adore you; won't be pitted against you by any invasion of our personal journeys. Sharon.''