Caitlyn Jenner
Meet Caitlyn Jenner: Bruce Jenner's new identity debuts on the cover of Vanity Fair magazineReuters

After her public debut as a woman on the cover of Vanity Fair magazine proved an internet sensation, Caitlyn Jenner has set a new world record.

The transgender Olympian, formerly known as Bruce Jenner, has amassed one million Twitter followers in four hours, the fastest time in the history of the social-networking site.

The incredible feat means that the 65-year-old celebrity has beaten former Twitter king President Barack Obama, who reached the milestone in five hours and held the title for two weeks.

Jenner's gender transition has been trending on both Facebook and Twitter since 6pm BST on Monday (1 June). At the time of writing, Jenner had reached a total of 1.9m followers, with her Twitter fanbase continuing to grow.

Jenner launched her certified account to coincide with the unveiling of her female identity on the latest issue of Vanity Fair wearing a cream corseted bodysuit along with the headline "Call me Caitlyn".

"I'm so happy after such a long struggle to be living my true self. Welcome to the world [of] Caitlyn. Can't wait for you to get to know her/me," her Twitter bio reads.

In the behind-the scenes video for the Vanity Fair photo-shoot captured by renowned fashion photographer Annie Leibovitz, Jenner explained why she decided to transition in the later years of her life.

"If I was lying on my deathbed and I had kept this secret and never ever did anything about it, I would be lying there saying, 'You just blew your entire life,'" she said.

"Bruce always had to tell a lie. He was always living that lie every day. He always had a secret from morning until night. Caitlyn doesn't have any secrets. As soon as the Vanity Fair cover comes out, I'm free."

In April, the gold-medallist put an end to months of speculation about his increasingly feminine appearance during an ABC two-hour special with Diane Sawyer by boldly declaring: "For all intents and purposes, I am a woman."

"My brain is much more female than it is male. That's what my soul is. Bruce lives a lie. She is not a lie. I can't do it anymore," he explained.