PLEASANTON — “Game of Thrones” star Hafthor Bjornsson came up just a wee bit short in his attempt to break his own “unofficial” record in the over-the-bar weight toss Sunday at the Scottish Highland Gathering & Games at the Alameda County Fairgrounds.

With three attempts heaving the 56-pound weight over the bar, Bjornsson — known as “The Mountain” on the hit HBO fantasy drama — did not break his current record of 19 feet, 3 inches by a mere inch.

In earlier attempts at a lower height, he had easily cleared the record of 19 feet, 4 inches, but came up short when it counted. He missed clearing the bar on the first try, and hit it with the weight on the last two attempts.

After beating current official record holder Mike Zolkiewicz, a personal trainer from Massachusetts, in a one-on-one showdown at 18 feet in the “pro class,” Bjornsson decided to go for a new “unofficial” record hoisting the weight that resembles a kettle bell. Like all the other competitors in his class, Bjornsson stood with his back to the bar and tossed the weight over﻿ his shoulder.

The Mountain’s current record, set last May, isn’t considered official because when he achieved it he hadn’t competed in the seven other strength events at the games. He also only competed in the weight-over-the-bar event at Pleasanton. But that distinction was clearly lost on his fans in attendance as they cheered “Let’s go, Mountain!”

“It was a treat seeing him at work,” said Tina Blease, of San Jose.

Bjornsson, 26, who received a $5,000 appearance fee, signed autographs before the event and, like a true Hollywood star, had to make a hasty retreat to jet off to Ireland for a “Game of Thrones” shoot.

When he’s not throwing his 420-pound frame around for the series, the Icelandic giant competes in a variety of strongman events worldwide, but he’s still best known for his “Game of Thrones” role.

Waiting in the lower grandstands for Bjornsson’s appearance, Taso Sporidis, of Washington, D.C., a “Game of Thrones” fan, didn’t realize the actor competed in strongman events.

“I’m still mad at him for killing the Viper” (a character on the show), says Sporidis.

Sporidis’ father-in-law, Nick Bench, of Monterey, was decked out in full Scottish attire, including a kilt, tam and leather pouch known as a sporran. He also didn’t know The Mountain would make an appearance.

“I basically come to hear the piping,” said the avid bagpiper.

The imposing 6-foot-9 behemoth started out as a basketballer and played center on Iceland’s national team before knee and ankle injuries ended his career. In 2008, Bjornsson met the dean of Icelandic strongmen, four-time “World’s Strongest Man” winner Magnus Ver Magnusson, who thought he had the physique to be a strength sports champion.

Encouraged, Bjornsson began to focus on strongman events and has racked up titles. In 2010, he came in third in “Iceland’s Strongest Man Competition” and has won the event every year since. He also took “Europe’s Strongest Man” title in 2014 and placed second by just half a point in the “World’s Strongest Man” competition — a contest that involves lifting cars and heavy stones as well as towing big rigs — held last year in Los Angeles.

In addition to setting the world record for throwing a washing machine (15.4 feet) earlier this year, The Mountain (also known by his full “Game of Thrones” character name, Ser Gregor “The Mountain That Rides” Clegane) has another unusual strongman resume builder: toting a 32-foot, 1,433-pound Viking ship mast.

Bjornsson took the timber a whopping five steps, smashing a 1,000-year-old record for the feat held by Orm Storoltgsson, who was only able to move the mast a mere two steps. And unlike Storoltgsson, Bjornsson didn’t end up breaking his neck in the process.