Morgan Boyes has joined Livingston from Liverpool on an 18-month deal, with the option for a further year.
Boyes, who has been capped by Wales Under-21s, is Livingston's first signing of the January transfer window.
"I believe we will be very good for one another," said manager David Martindale.
"He is a young player with a massive amount of development and potential still to come. Morgan is a left centre left-half with a very good left foot."
Livi's next scheduled match is against Scottish Premiership opponents Dundee on 18 January.
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