Bayer Leverkusen have secured a deal to sign Julian Baumgartlinger from Bundesliga rivals Mainz 05.
The midfielder had another three years left to run on his contract at the Coface Arena, but Leverkusen have activated his £3m release clause.
"Baumgartlinger fully meets our requirements," sporting director Rudi Voller told the club's official website.
"A character of a player with leadership qualities, ambitious, physically strong with strategic ability. He will improve the quality level of our squad and increase the competition for places."
The 28-year-old added: "I had a great and successful time at Mainz. Now I want to take the next step.
"Bayer 04 Leverkusen are an established Champions League club and they've regularly been in the competition for years. I want to see how I compare at this level."
Baumgartlinger is expected to feature for Austria at this summer's European Championships in France.