Vitalii Mykolenko will wear the number 19 shirt for Everton.
The Ukraine international completed a move to the Blues on 1 January, signing from Dynamo Kiev for an undisclosed fee on a four-and-a-half-year deal.
Mykolenko, who is primarily a left-back but can also operate at centre-back and in a more advanced position on the left flank, becomes manager Rafa Benitez's first signing of the winter transfer window.
James Rodriguez was the most recent incumbent of the squad number before moving to Qatari club Al Rayyan for an undisclosed fee in September.
Other former Blues to don number 19 include Bryan McBride, Gerard Deulofeu, Oumar Niasse and Djibril Sidibé.