Is it a bird? Is it a plane? Is it a dimension-jumping spacecraft choc-full of extraterrestrials?
We don’t know, and nor does Oscar-winning actor Russell Crowe, who recently took three snaps of a UFO flying by the window of his office in Woolloomooloo, Australia.
He claims to have had his camera in place to capture images of fruit bats and said the UFO shots he caught were "a big surprise."
An apparently shaken Crowe took to Twitter last night to share a video of the three photos with his followers:
Faced with scepticism about his snaps, the Les Mis star insisted that the glowing objects in the photos weren’t caused by lens flare or the position of the camera.
“Canon 5D, No Flash, can't be a lense (sic) flare because it moves, camera is fixed,” he tweeted. “The camera is on a balcony not behind glass.”
Crowe also dismissed the suggestion made by one of his followers that the object in the photos was a yacht. “We considered that,” he wrote. “But to cover that distance in 4.5 secs it would have to be travelling at 80km per hour.”
Whatever the object was, it's currently unidentified and certainly appeared to by flying. So has Russell captured something truly out of this world?
"While there's not necessarily any reason to suspect Russell Crowe of creating a deliberate fake, we should remember just how many supposed UFOs turn out to be cases of misidentification," said Fortean Times editor David Sutton.
"While Mr Crowe might have accidentally captured evidence of an alien invasion, I'd say, on the basis of past experience, that the odds are heavily against him."
What do you make of Russell's photos? Let us know in the comments below.