'The England youth worldwide will now be part of the Liverpool squad for Sunday's friendly against Napoli in Edinburgh and the subsequent training camp in Evian'.
Reds' first signing in the transfer window was 17-year-old centre-back from the Netherlands, Sepp van den Berg.
Elliott made three competitive appearances in total for the Cottagers.
He then became the youngest ever player to feature in the Premier League when he came off the bench against Wolves towards the end of last season aged 16 years and 30 days.
Furthermore, he will part of the first-team training camp In Evian.
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Elliott will not turn professional until his 17th birthday, which is in April, and the maximum length of contract he can sign with Liverpool will be three years.
Unfortunately, Liverpool failed to note how much 16-year-old Harvey Elliott cost.
The Surrey-born midfielder became the Premier League's youngest ever player when he made a second half appearance against Wolverhampton Wanderers in May.
'I'll work as hard as I possibly can for the club and I feel Anfield is the flawless place for me to develop and progress as a player'.