Los Angeles, California - Fans couldn't believe how grown-up Kim Kardashian's 4-year-old son Psalm West looked in a new Instagram video!

In a viral video posted to Khloé Kardashian's Instagram on Friday, Psalm can be seen dancing to his 10-year-old sister North's verse in their dad Kanye West's song TALKING.

Psalm can be seen dancing along with his sister Chicago (6) as well as his cousins True (5) and Tatum (1) – all rocking their pajamas!

Aunt Khloé also makes an adorable dance cameo in the video, which she simply captioned, "A medley."

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Fans were shocked by Psalm's appearance in the video, however, and many confessed to barely recognizing Kim and Ye's youngest child!

"Who is the lil boy.. is that Psalm?” one fan asked in confusion as a second echoed, "Is that Psalm??? OMG !!"

"I had to make an educated guess about Psalm," joked a third.

Kardashian fans couldn't get over how big Psalmy had gotten!

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"That’s Psalm with True and Chicago?? wow he got big," said one follower with another adding that he "grew up so much."

Did you recognize Psalm West in this viral video?