First lady of the US Melania Trump's "Be Best" initiative is facing the heat after her husband President Donald Trump made a jibe at teenage climate change activist Greta Thunberg.

After the US President suggested the 16-year-old activist to "work on her anger management problem" and "chill," the netizens have been reminding Donald Trump of his wife's "Be Best" platform- a public awareness campaign that focuses on well-being for youth, and advocates against cyberbullying and drug use. #BeBest hashtag is trending on Twitter since then, with users asking the 49-year-old to stand up to her husband and condemn his words, reports Newsweek.

"Seriously @FLOTUS if you don't call out the President right now delete the #Bebest movement," a user wrote while another tweeted, "Hey @FLOTUS...since you're so outraged when children are used and bullied...how about a public rebuke of your sociopath husband for bullying a 16 year old girl with Asperger's? Oh right, I forgot, "I really don't care, do you?" #BeBest #Melania #Trump #GretaThunberg."

On Wednesday, after Time magazine announced Thunberg as its "person of the year" for her activism on climate change that has attracted attention from all over the world, the POTUS who had earlier also targeted the activist, called the selection "ridiculous."

"So ridiculous. Greta must work on her Anger Management problem, then go to a good old fashioned movie with a friend! Chill Greta, Chill!" the 73-year-old wrote on Twitter.

So ridiculous. Greta must work on her Anger Management problem, then go to a good old fashioned movie with a friend! Chill Greta, Chill! https://t.co/M8ZtS8okzE

— Donald J. Trump (@realDonaldTrump) December 12, 2019

And while the president has been facing the wrath of Twitter users ever since, Thunberg herself did not back down from trolling him. In response to the president's criticism, the activist changed her Twitter bio to "a teenager working on her anger management problem. Currently chilling and watching a good old fashioned movie with a friend."

Climate activist Greta Thunberg
Hours after her impassioned speech against world leaders for failing to act on climate change, Donald Trump described Greta Thunberg as a 'very happy young girl looking forward to a bright and wonderful future' Photo: AFP / Johannes EISELE Johannes Eisele/AFP

She also responded to the allegations that she is being used as a political weapon and wrote: "I'm sometimes called 'political'...If anyone thinks that what I and the science are saying is advocating for a political view - then that says more about that person than about me. That being said - some are certainly failing more than others."

If anyone thinks that what I and the science are saying is advocating for a political view - then that says more about that person than about me.
That being said - some are certainly failing more than others.

— Greta Thunberg (@GretaThunberg) December 12, 2019

The Sweden national in the past also hit back at politicians through her Twitter bio. Earlier in September, when Russia President Vladimir Putin described her as "kind," before adding dismissively that "no one has explained to Greta that the modern world is complex," Greta changed her bio to: "A kind but poorly informed teenager."