The 26-year-old reality star, who was devastated after her close pal was found dead at her London home in July, was furious after the impostor used the fake profile to contact her.
Using the name AmyjMermaid to impersonate the Back To Black singer's Twitter account, AmyJadeMermaid, the impostor tweeted: 'Miss ya darling!'
Osbourne replied: 'That's not f****** funny, you disrespectful t***.
'You should be ashamed, don’t ever tweet me again. I'm going to have you thrown of [sic] Twitter! If you have one ounce of dignity or self-respect you will delete this fake Amy profile or I will do it for you!'
She added: 'I just can't believe the nerve of some people! Why would anyone make a fake profile and pretend to be Amy W? That is just sick!'
Osbourne was quick to complain to moderators on the social networking site, who are said to have agreed to take down the profile.
She added: 'Good news everyone, I have emailed Twitter and the hole with [the] fake Amy profile amyjmermaid will be taken down in a matter of hours!'