Poland forward Robert Lewandowski became the second top Borussia Dortmund player to leave for archrival Bayern Munich in less than a year when he agreed to terms on Saturday to join it as a free agent at the end of the season.

In another heart-breaking move for Dortmund coach Juergen Klopp, the Bundesliga leading scorer signed a five-year contract with the current world, European and Bundesliga champion.

The 25-year-old will see out the rest of his contract with Dortmund, which runs until the end of this season, before joining Bayern on July 1, the Bavarian club said in a statement.

"We are satisfied that this transfer has gone through," said Bayern's chief executive, Karl-Heinz Rummenigge. "Robert Lewandowski is one of the best forwards in the world, and he will strengthen the Bayern squad."

Last April, Mario Goetze, one of the jewels of Dortmund's youth academy, also left for Bayern in a shock 37 million euro ($50.37 million) deal that the supporters have barely digested.

Lewandowski's departure did not create the same shockwaves in Dortmund as it had been expected for a long time but it is still a bitter pill for Klopp and baffling for its fans.

Dortmund has one of the most loyal set of fans in Europe with about 80,000 regularly filling its stadium, including the 25,000 who pack the famous Suedtribune's standing area.

Bayern dominance

Lewandowski's move to Munich will add to concerns about Bayern's growing dominance in Germany.

It won the Bundesliga by a massive 25-point margin from Dortmund last season and leads this season's championship by seven points at the halfway mark with an unbeaten record.

The clinical Poland international will have to battle for his place as Bayern tends to field only one striker, with Croatia's Mario Mandzukic the favored choice at present.

While Bayern has continually strengthened its squad over the past few seasons, Dortmund has lost several top players, including Japan's Shinji Kagawa, who joined Manchester United.

Like Goetze, Lewandowski was instrumental in helping Dortmund win successive Bundesliga titles in 2011 and 2012.

However, he made it clear in September he wanted to join Bayern and a move was widely seen in Germany as just a matter of time.

Lewandowski fell out with Dortmund's bosses over his failed attempt to join the treble winners in the close season but later said ties with the club had been mended and accepted the fact he would spend one more season there.

Lewandowski, whose pace and control make him perfect for Dortmund's high-tempo game, has scored 11 league goals this term. He was the Bundesliga's third-highest scorer with 22 in 2011-12 and second in the scoring charts with 24 last season.

Rummenigge, meanwhile, ruled out speculation of a move for Chelsea defender David Luiz.

"There's a lot of speculation ... we are being linked with David Luiz and other Spanish players at the present time," he said.

"Let me state this very clearly: it's all of no interest whatsoever to us. What I'd personally like is for Holger Badstuber to make a comeback."

German centerback Badstuber underwent a fourth operation in October on right knee ligaments he has twice ruptured.