Born and raised in Brussels, Belgium on 3 February 2005, within a family of Spanish and Italian descent, Matias began his playing career with Anderlecht and Mechelen in his native homeland before joining Lille's Academy in 2014.
He spent six years in Northern France before joining Gent's youth system as a 15-year-old.
The Belgian forward featured for Jong KAA Gent, Gent's reserve team, during the 2022/23 season before making his first team debut at the age of 18 during a Conference League match against İstanbul Başakşehir F.K in March 2023.
Matias made his Belgian top-flight bow a month later after featuring in the closing stages of Gent's 5-0 away win against RFC Seraing.
Matias' breakthrough campaign at first-team level saw the promising youngster rewarded with a contract extension in June 2023, tying him to the club until 2026.
In 2023/24, the Belgian teenager accrued 19 appearances for Gent and played a key role in helping the Belgian Pro League outfit secure European qualification.
During the 2023/24 Belgian Pro League play-offs, he played in each of the ten matches and netted seven goals as well as providing two assists.
Four years after departing Lille, Matias returned to the Ligue 1 club for a second playing spell, penning a five-year deal with Les Dogues.
He recorded four goals and four assists during his maiden season at the Stade Pierre-Mauroy despite tearing a ligament in his left ankle in January 2025.
The exciting Belgian also made his full UEFA Champions League debut during a 3-1 win against Atlético Madrid in October 2024, playing in front of over 61,000 spectators at the Riyadh Air Metropolitano.
Last season, Matias enjoyed his best campaign in front of goal after registering 15 goal involvements across all competitions, including eight strikes in the French top-flight as the club carried out a 13-game unbeaten league streak to secure a third-place finish.
During Lille's positive run-in, the 21-year-old provided five goals and two assists in seven Ligue 1 outings and ranks amongst the top ten list of players aged 21 or under in Europe's top five leagues for goals and assists.
He also featured in Lille's Europa League campaign before exiting at the last 16 stage against eventual winners Aston Villa following a 3-0 aggregate defeat.
Matias has represented Belgium throughout numerous age groups at youth level before making his senior international debut for the Red Devils in June's pre-World Cup friendly win over Croatia.
Despite an approved request to switch allegiances to Spain in February 2025, Matias ultimately never represented La Roja at any level and, in May 2026, his request to switch international allegiance back to Belgium was approved by FIFA.
A day later, he was called up to Belgium's 26-man squad for the 2026 FIFA World Cup and featured as a substitute in all three of his country's Group G fixtures in North America as Rudi Garcia's side reached the quarter-finals before exiting against eventual champions Spain.
Matias, who will wear the number 20 shirt, could be line for his Newcastle United debut on Saturday when the Magpies face AFC Bournemouth at St. James' Park (kick-off 12:30pm BST). The 21-year-old, who stands at 6 foot tall, said: “I’m really, really happy to be here and very proud to be at such a big club. “I spoke to the head coach and he really showed how much he wanted me to be here. In terms of my own career progression, it made complete sense to come so I didn't hesitate at all. “I know the club, I know about the stadium, I know it's a fantastic atmosphere. I've followed the team. What I've seen is a team that's very ambitious, wants to attack, get forward, really chase teams and go after them, and that's really something I want to take part in as well. “I'm still young, I'm still hungry, and that's why I'm here, and I want to make that progress with Newcastle. I can't wait to start the wonderful adventure here."
