It is the biggest transfer fee in Bundesliga history: Athletic Bilbao's Javi Martinez joined Bayern Munich on Wednesday for 40 million euros ($50 million).

The 23-year-old passed his medical with the club in the early hours of the morning, after travelling to Munich directly from the Spanish national team camp. He helped lead Bilbao to second place finishes in both the Europa League and Copa del Rey last season.

"I am very happy to be here and I hope to (return) all your support in the first match," Martinez told Bayern's television channel FCB.tv.

Martinez has emerged as one of Spain's rising talents in recent years, having already collected eight caps with his country's senior national team. He was a member of the Spain teams that won both the 2010 World Cup and 2012 European Championship, and represented the Under-23 team at this summer's London Olympics.

He is the fifth high-profile player to join the Bavarian giants this summer after Dante (Borussia Mönchengladbach), Claudio Pizarro (Werder Bremen), Xherdan Shaqiri (FC Basel) and Mario Mandzukic (Wolfsburg).

It was not the most straightforward deal, having proved something of a protracted affair. Ahead of the signing, Bilbao issued a statement that they had not given the player permission for the trip to Germany in which he completed the medical.

"This was without question a very complicated transfer," explained Bayern chairman Karl-Heinz Rummenigge. "We are all the happier that he is finally with us as a result."

Undoubted talent, high price to pay

While Martinez is widely seen as Bilbao’s second-best player, after striker Fernando Llorente, the amount to be paid by Bayern has raised some eyebrows.

"I don't think anybody else really would have paid 40 million euros for him," Madrid-based journalist Dermot Corrigan, who writes for the Irish examiner, told DW. Corrigan mentioned that both Spanish giants Real Madrid and Barcelona had previously enquired with Bilbao, but were put off by the price tag.

Martinez, who can play in both the center of defense and midfield, joins a crowded cast that includes players like Bastian Schweinsteiger, Luis Gustavo, Toni Kroos, Holger Bastuber, David Alaba and Jerome Boateng.

While there's no lack of competition for a first-team place, Corrigan said he believed Martinez was capable of making his mark. "He's a good engine, he's a good passer, technically very good, he's not going to be intimidated - I don't think - by the style of play. From what I have seen of Bayern Munich, I could see him earning his place in the team. He's young as well, so he's only going to get better."

The Basque player smashed the previous Bundesliga record transfer of 30 million euros, also set by Munich club when they purchased striker Mario Gomez from Stuttgart in 2009. Borussia Dortmund hold the record German transfer fee for a club other than Bayern, having spent 25 million euros for then Parma striker Marcio Amoroso of Brazil in 2001.