The Spanish wonderkid - who turned 18 last week - has inherited the iconic Barca number from Ansu Fati, who has joined Monaco on a season-long loan deal.
Yamal's new number was confirmed at an event with the winger and his family in celebration of his new contract, which will keep him at the Catalan club until 2031.
Messi wore the number 10 shirt at Barca from 2008 until he left for PSG in 2021. The Argentine legend became Barcelona's all-time top goalscorer while winning 10 La Liga titles and four Champions League crowns during his time with the club.
Yamal told reporters: "What this renewal means is that I'll continue playing for the club of my life, I'll continue enjoying it. I'm under no pressure; I'll continue enjoying myself with a different number."
The teenager will bid to live up to Barca icons Messi, Ronaldinho and Diego Maradona when he dons the famous number.
He said: "I'd keep everything from each of them. I'm grateful for the club's trust and I'll try to continue that legacy."
Yamal is already regarded as one of the best players in the world but insists that he is "indifferent" to both positive and negative opinions about him.
He said: "The truth is that I'm indifferent to both criticism and praise, unless it comes from my family or people very close to me, because otherwise, one day I'll be very high and the next I'll be very low."
The star is now determined to lead Barca to Champions League success and Spain to World Cup glory next season.
Yamal said: "I haven't won the Champions League, so I want to win the Champions League and the World Cup. Winning the title we've been missing, which was the Champions League, and continuing to grow and play just as well."