Martinez, who idolises Lionel Messi and former Liverpool winger Luis Diaz, won't officially become a Liverpool player until he turns 18 next summer. He has made the trip to England with his agent, Daniel Neumuller, and will put pen to paper on a five-year contract once everything is finalised, having fought off competition from Borussia Dortmund and Barcelona.
Liverpool's interest in the teenager was first reported by Daily Mail Sport back in May. Martinez shot to prominence by captaining Colombia to victory at the South American Under-17 Championship, wearing the number 10 shirt and setting up several goals along the way.
Martinez is set to spend the coming year still on Atletico Nacional's books, giving him time to keep developing at a club he already knows well while Liverpool track his progress from afar.
The move forms part of a broader push by Liverpool to build up their academy ranks with young talent from across the world. The club have also completed the signing of Scotland Under-16 captain Dara Jikiemi from Celtic on a five-year deal, and agreed a move for striker Michael Mulholland, who is set to arrive from Northern Irish side Crusaders once he turns 16.
Liverpool are also continuing to monitor further additions to their academy, having already secured deals for young defenders including Jeremy Jacquet and Giovanni Leoni for the first-team squad, as the Merseyside club look to strengthen their long-term recruitment pipeline both domestically and internationally.
Standing over six feet tall, Martinez has drawn early comparisons to former Ballon d'Or winner Kaka for his elegant playing style, dribbling ability and range of passing, despite having yet to make his senior debut for Atletico Nacional.
He is expected to continue representing Colombia at youth level before completing his move to Anfield, with Liverpool viewing him as a long-term investment in their midfield options rather than an immediate first-team addition.