Soccer-Dortmund's Lewandowski to join Bayern next season

Jan 4 (Reuters) - Borussia Dortmund striker Robert Lewandowski will join Bundesliga arch-rivals Bayern Munich next season, the German champions said on Saturday.

The Poland international, who helped Dortmund win successive Bundesliga titles in 2011 and 2012, has signed a five-year contract, Bayern said on their website (www.fcbayern.de). (Reporting by Brian Homewood; Editing by Ken Ferris)