Dwayne "The Rock" Johnson is now the most-followed American man on the social media platform Instagram.

The wrestler-turned-actor, known for his role as Luke Hobbs in the Fast & Furious series, beginning with Fast Five (2011), celebrated the milestone on Instagram.

The 48-year-old wrote in a post last Thursday (Oct 8): "Here's what I've learned these past few weeks and maybe, you can find value in this take away and apply it to your own life. Always speak your truth.

"And when you do speak your truth - do your best to speak with dignity, compassion, respect, poise and empathy.

"Even when the conversations get uncomfortable - when you approach with respect and care - on the other side of discomfort - is clarity and progress."

Though he did not specify what speaking his truth meant, Johnson had earlier publicly endorsed American politicians Joe Biden and Kamala Harris in the US presidential election - his first public presidential endorsement of his career.

With over 200 million followers, Johnson has become the third most-followed star in the world.

Portuguese football superstar Cristiano Ronaldo has the biggest Instagram following in the world at 239 million, while singer Ariana Grande is the biggest female Instagrammer with 203 million.