To celebrate her birthday on January 3, Ms Thunberg also changed her bio to reflect that she has turned 17 and went to the weekly Fridays for Future climate protest outside the Swedish parliament building in Stockholm
Greta Thunberg has changed her name to Sharon on Twitter, in a humorous response to a video clip of a TV quiz show contestant who appeared to have no idea who she was.
While appearing on BBC's Celebrity Mastermind, British actress Amanda Henderson was asked to name the teenage climate activist who has made a difference at a very young age.
Baffled Henderson shook her head and guessed: "Sharon."
The moment went viral and has been viewed more than five million times since the show aired on BBC 2 on January 2.
Soon after the video goes viral, Ms Thunberg changed her Twitter handle name to 'Sharon' on Friday afternoon.
Ms Thunberg also changed her bio to reflect that she has turned 17 - as Friday was also her birthday.
She celebrated her birthday by going to the weekly Fridays for Future climate protest outside the Swedish parliament building in Stockholm.
Ms Thunberg has been known to have fun with her Twitter profile.
Last month, US President Donald Trump tweeted: "Greta must work on her anger management problem, then go to a good old fashioned movie with a friend! Chill, Greta, Chill!"
In response, Ms Thunberg edited her bio to say she was "a teenager working on her anger management problem. Currently chilling and watching a good old fashioned movie with a friend".
Earlier that week, she changed her bio to say she was a "pirralha" - the Portuguese word for brat - after Brazilian President Jair Bolsonaro criticised her for highlighting the plight of Brazil's indigenous people.
"Greta's been saying Indians have died because they were defending the Amazon," Mr Bolsonaro had told reporters. "It's amazing how much space the press gives this kind of pirralha."
In October she changed her bio to "a kind but poorly informed teenager" - which was exactly how Russian President Vladimir Putin had described her at a conference in Moscow.
In September President Trump posted a video of her speaking emotionally at the UN conference and sarcastically commented: "She seems like a very happy young girl looking forward to a bright and wonderful future."
She changed her bio accordingly: "A very happy young girl looking forward to a bright and wonderful future".