While her grandfather, US President Donald Trump, is busy with politics, five-year-old Arabella Kushner has been brushing up on her Mandarin skills and even sang a Chinese New Year song.

Her mother, Ivanka Trump on Thursday (Feb 2) posted a video on Instagram of Arabella singing a "Happy New Year" song in Mandarin as she swayed, holding a red dragon puppet on strings.

The first daughter wrote: "Arabella singing a song she learned for #ChineseNewYear. Wishing everyone an amazing year to come during these days of celebration. Xin Nian Kuai Le (Happy New Year)!"

The post has garnered more than 800,000 views.

A day earlier, Ms Trump took Arabella to a Chinese New Year party at the Chinese embassy in Washington where they watched a musical performance that included Chinese opera, reported the Daily Mail.

Ms Trump even called Arabella her "translator", according to a CNN article.

Arabella's fluency is no surprise as she started learning Mandarin from a Chinese nanny since she was 16 months old, according to a South China Morning Post interview with Ms Trump.

Neither is Arabella new to social media fame.

In November last year, a video of her wearing a traditional qipao and reciting ancient Chinese poetry trended on Sina Weibo after Mr Trump was announced as President-elect.

Chinese netizens were quick to warm up to the little girl, praising her recital.

Arabella, the eldest of Ms Trump's children with husband and Mr Trump's senior adviser Jared Kushner, has two siblings - Joseph Frederick, 3, and Theodore James, who was born in March last year.

Correction note: In an earlier version of the story, it was stated that Arabella was holding a dragon puppet on strings. It should be a lion. We are sorry for the error.