Audi will buy 2.5 million shares in the Bundesliga outfit as part of the agreement which was signed on Thursday at Audi's headquarters in Ingolstadt.

The two parties have been in partnership since 2002 but this deal represents the first time Audi have invested money in the Bavarian club.

Audi's outlay, to be paid in three instalments between March next year and July 2011, secures them a 9.09% stake in Bayern.

"With this direct financial partnership with FC Bayern Munich AG, two successful leading brands are now even more on the ball," said Audi AG chairman Rupert Stadler.

"I am looking forward to many great moments with the club.

"As well as the financial engagement, plans are in the pipeline which should strengthen the global presence of both brands."

Audi's marketing director Peter Schwarzenbauer added: "We have forged a close partnership since becoming Bayern's automobile partners in 2002 and now we, as a premium car manufacturer, are joining one of the world's greatest and fantastically led football clubs."

Bayern chairman Karl-Heinz Rummenigge welcomed the extension of the partnership with a "reliable, professional and friendly premium partner of FC Bayern".

"I am sure that this partnership will open many new opportunities to us worldwide," he added.

It is believed Bayern plan to use the money from the deal to pay off debts related to the construction of the Allianz Arena to make the stadium the club's own property.