The former Milram rider had agreed to ride for the Pegasus Sports team but was left struggling to find a place in the peloton after the Australian team failed to secure a Professional Continental licence.
He is the seventh new arrival at Team Sky for 2011, joining David Appollonio, Alex Dowsett, Jeremy Hunt, Michael Rogers, Rigoberto Urán and Xabier Zandio in the 30-man squad.
"Christian is a super strong all-rounder who has had some terrific results, but I still don't think we have seen the best of him yet and hopefully we can help him fulfill his massive potential at Team Sky," team principal Dave Brailsford said in a statement from the British team.
"His personality is one that will fit well into the team and we are delighted to have such an experienced rider on board. He has a lot of capabilities in a lot of areas and will increase the depth of ability we have here. It's exciting to have secured his services."
Knees is 29 years old and has been a professional for seven years after beginning his career with Team Wiesenhof in 2004. He won the 2010 German national title with a solo attack. He made his eighth Grand Tour appearance at the 2010 Tour de France and took two top-ten finishes in the opening week.
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Stephen is the most experienced member of the Cyclingnews team, having reported on professional cycling since 1994. He has been Head of News at Cyclingnews since 2022, before which he held the position of European editor since 2012 and previously worked for Reuters, Shift Active Media, and CyclingWeekly, among other publications.
