The deal is subject to international clearance.
Alberto, 20, made his first-team debut for Sevilla on 16 April 2011 against Getafe CF but failed to establish himself at the Estadio Ramón Sánchez-Pizjuán, making just seven senior appearances for the Sevillistas from 2010 to 2012.
Thus, in August 2012, the 20-year-old was loaned to Liga Adelante side FC Barcelona B on a one-year deal.
While on loan at the Mini Estadi, Alberto bagged 11 goals and 17 assists in 38 appearances, attracting interest from a number of top European clubs.
“We are all delighted that Luis has decided to join Liverpool,” Liverpool manager Brendan Rodgers told the club’s official website.
“He has the correct footballing profile and mentality to be a Liverpool player.
“I look forward to working with him to develop his talent and he joins a group of young exciting players at our club.”
Alberto, who can play anywhere across the front line, is delighted with the deal.
“I feel very excited, I’ve never felt so excited before but I’m very happy,” added the 20-year-old ace.
“I think I am the happiest man on earth. I have come here to enjoy moments with the supporters – and I know the supporters will help me to never walk alone.
“I hope that between us all we can make this club one of the greatest in the world, once again.”
Celtic sign Van Dijk
Scottish Premier League champions Celtic F.C. have completed the signing of Holland Under-21 international defender Virgil van Dijk from FC Groningen for a reported fee of £2.5 million, according to Sky Sports.
Van Dijk, 21, is looking forward to playing in the UEFA Champions League next season, and rightfully so.
The 21-year-old defender had been linked with a number of English clubs, including Everton, prior to agreeing to move to Celtic Park.
“It feels very good and I’m very excited to be here,” the 21-year-old told the club’s official website. “I’m really looking forward to playing here for Celtic.
“Celtic is the biggest club in Scotland and they also play in the Champions League. They’re a fantastic club and when Celtic came in for me I was so excited. Everything here is good so I can’t wait to get started.
“I hope to play many games for my country in the future but first of all I want to make things happen here.”
Van Dijk, who made his first-team debut for Groningen on 1 April 2011 against ADO Den Haag, scored seven goals in 62 appearances for the Dutch Eredivisie side.