PETA has warned Lady Gaga that she could become "a target" for the organisation after apparently starting to wear fur.

People for The Ethical Treatment of Animals Senior Vice President Dan Mathews branded Gaga "a turncoat" after she previously commented on The Ellen DeGeneres Show that she hates the cruel practices behind fur.

In an open letter obtained by the website Gossip Cop, Mathews said to Gaga: "Recent photos of you in fox and rabbit and with a wolf carcass make it appear that you have amnesia . . . What happened? Are your stylists telling you that it's fake, or are you a turncoat?

"By wearing those dumb furs in a heat wave, you're making yourself a target just like the mindless Kim Kardashian. As we plan our fall campaigns, please tell us whether what you gracefully told Ellen was heartfelt or just a pose."

Mathews also suggested to Gaga that her fashion choices may upset her devout gay fan base, most of whom he claimed are strongly against wearing fur.

"Many gays are animal advocates because we recognise that the same arrogance and indifference that some have toward animal suffering has at times been directed toward us personally because of our orientation," he wrote.

Gaga has yet to reply to PETA's letter, though she did reference the controversy over her outfits briefly on her social networking site, Little Monsters.

She wrote: "For those press and such who are writing about whether or not my fur is actually real, please don't forget to credit the designer HERMES. Thank You! LOVE, gaga."

PETA previously praised Gaga's "unwavering" anti-fur stance, though they took issue with her wearing a meat bikini for a Japanese magazine cover in 2010.

Kim Kardashian was flour-bombed at her perfume launch earlier this year by a woman linked to PETA.