Tila Tequila -- Negotiating Return to 'Celeb Big Brother' ... But Also Threatening Suit

Tila Tequila wants back on "Celebrity Big Brother" now that she's apologized for her comment supporting Hitler, and we're told she's negotiating with producers to return, but also giving them an ultimatum.

TMZ broke the story -- Tila was removed from the show after day 1 ... producers said they couldn't tolerate someone who supported Hitler. But Tila believes producers planned from the very beginning to feign shock and fire her to drum up publicity.

A rep for Tila tells TMZ the show did a thorough background check on the reality star before they signed her. The rep says Tila's pro-Nazi remarks in 2013 were readily searchable.

We're told producers and Tila are now discussing the possibility of her returning.