Heidi: Opossum with crossed eyes warmed hearts worldwide

Facebook friends and fans across the Twittersphere are mourning the loss of Heidi — the cross-eyed German opossum whose cute but confused countenance warmed hearts around the world.

The Leipzig zoo said Wednesday that the marsupial had been listless and unable to move for several weeks. A decision was made to put the three-and-a-half-year-old animal to sleep following repeated attempts to treat her.

"We carried out every possible test and treatment," zoo director Joerg Junhold said in a statement. "We made the final decision ... to relieve the animal from suffering and pain."

Within minutes of the announcement, Heidi was trending on Twitter and thousands of fans were leaving an outpouring of condolences on her Facebook page.

"How sad," wrote Rene Schaaf, from Heidi's home city of Leipzig. "This lovable creature enriched our daily lives, showing us that 'imperfect' can also be interesting and even beautiful."

Heidi first attracted attention at the end of last year after she was featured on a local television report about the nocturnal enclosure where she spent her final days.

A clip of the report went viral, giving rise to a fan page on Facebook that attracted more than 332,000 admirers from across the globe.

She was also featured on a TV show in the United States alongside the Oscars awards ceremony in February. The furry forecaster was asked to predict the winners — and correctly chose both the best actress and best actor.