A composite image of Kelly Osbourne and Lady Gaga. (REUTERS/Danny Moloshok/Carlo Allegri)

Lady Gaga has called on Kelly Osbourne to "set a standard of respect, compassion, and love" after the reality TV star revealed she had been cyber bullied by the Poker Face hitmaker's fans for harsh comments she made about the singer's weight.

Ozzy Osbourne's daughter hit the headlines last year when she told a U.K. talk show host she thought Gaga was pregnant when the pop star appeared onstage sporting a new curvy figure.

Fans didn't take kindly to the slimmed-down TV star's remarks and they took aim at Kelly for sparking gossip that forced their heroine to explain she had just put on a few pounds.

Gaga has now addressed Osbourne's bullying drama at the hands of her fans and encouraged the star to be more compassionate when she appears on her catty U.S. style series Fashion Police.

In an open letter to Osbourne posted on her LittleMonsters.com blog on Thursday, the singer wrote, "Everyday, through my music and public voice I choose to be positive and work towards a kinder and braver world with our community of followers. I encourage them to ignore criticism, stand up to bullies, know their own value and see that we are all the same and no one person is worth more than another.

"I have empathy for you Kelly, but I feel it culturally important to note that you have chosen a less compassionate path. Your work on E! with the Fashion Police is rooted in criticism, judgment, and rating people's beauty against one another. 'Appearance' is the most used reason for bullying in the world.

"Your show breeds negativity, and over the years has even become comedic in nature. It glorifies you and (co-host) Joan Rivers pointing in the camera, laughing, and making jokes about artists and celebrities as if we are zoo animals."

Referencing Osbourne's former fuller figure, Gaga adds, "What about your body revolution? It used to make me truly sad when I would hear people talk about your weight when you were younger, as I was bullied too. To see you blossoming into a beautiful slender woman who makes fun of others for a living is astounding.

"Why not help others? Why not defend others who are bullied for their image and share your story? I am pointing this out not to take a crack at your character, as we've met before and you're lovely. However, I urge you to take responsibility and accountability for the example that you are setting for young people.

"I cannot control my fans, and I discourage them from any negativity and violence, because that is wrong and hurtful - and I do feel badly that your feelings were hurt. However, we can all do our part in the media to set a standard of respect, compassion, and love. I wish for you to be treated with the kindness and respect that everyone deserves."