Amanda Bynes

The troubled star insulted the 20-year-old singer on the social networking site on Tuesday night when she called her ugly, but the 'Can't Be Tamed' hitmaker isn't being drawn into a public feud.

Speaking to radio station Hot 95.5, she said: "I won't even entertain that thought. I think it's all so sad and I don't want to add any fuel to that fire. It's so sad to me.

"I was rooting for her comeback until she started attacking me, and I just thought it was hilarious that she mentioned my name the moment I was the worldwide trending topic on Twitter.

"It's just funny the moment you're a trending topic how many people want your name to come out of their mouth, so somehow they can associate and maybe they can become a trending topic."

Amanda, 27, also insulted rapper Drake on her Twitter account last week.

Although she deleted the initial tweet, she had written: "Drake has the ugliest smile, ugly gums uneven teeth ugly eyes."

She later added: "I won't deny calling @drake ugly."