OJ Simpson's first tweet drew no shortage of doubters and cynics on Twitter. (File photo)

Just days after the 25th anniversary of the gruesome double murder of which he was accused but acquitted, OJ Simpson has opened a Twitter account with a vow to do "a little getting even."

"Hey, Twitter world, this is yours truly," the former football star and actor says in a video that, for now, is his only post.

Simpson lawyer Malcolm LaVergne confirmed to CNN that the account was authentic, as was the video, apparently filmed by Simpson on a smartphone in the yard of a Las Vegas residence.

Simpson's Twitter account -- @TheRealOJ32 -- refers to the number he wore on his jersey as a star running back at the University of Southern California and then with the NFL's Buffalo Bills.

As of 18 hours after its posting, the video had drawn 60,000 "likes," and Simpson had accrued no fewer than 254,000 followers, a number rising by the minute.

A smiling and relaxed-looking Simpson promises in the video that soon "you'll get to read all my thoughts and opinions on just about everything."

Warning that "there's a lot of fake OJ accounts out there," he says that this one is official, saying, "It should be a lot of fun."

Simpson then adds -- raising a few eyebrows, no doubt -- "I've got a little getting even to do."

June 12 was the 25th anniversary of the murders in Los Angeles of Nicole Brown Simpson, the football player's ex-wife, and her friend Ron Goldman.

Simpson, arrested after a slow-speed car chase broadcast live on TV, was accused of the murders, based partly on bloody footprints and a bloody glove found at the scene.

After one of the most sensational trials in decades, a jury found him not guilty.

Yet in a wrongful death lawsuit brought by the victims' families, he was held responsible and ordered to pay millions in damages.

Subsequently convicted of robbery in Las Vegas, he served time in prison before being released in October 2017.

His lawyer, LaVergne, insisted that Simpson "will not be negative" on Twitter, calling him "the most positive person I've ever met."

But Simpson's post drew no shortage of doubters and cynics on Twitter.

"I'm sure this will only bolster Twitter's widespread reputation for civil, nuanced discussion," said one poster.

"Too soon," added another.