The actor has agreed to play the new business partner of Phil (Ty Burrell) in the ABC comedy, Entertainment Weekly reports.
Kinnear's character Tad, who is described as successful and athletic, soon begins to impress Phil.
However, Claire (Julie Bowen) does not get on well with him.
Kinnear recently starred in the miniseries The Kennedys and has also had a guest role in Friends.
His movie credits include parts in Little Miss Sunshine, Green Zone, Ghost Town, We Were Soldiers, You've Got Mail and As Good As It Gets.
Modern Family airs on Wednesdays at 9/8c on ABC in the US and on Fridays at 8pm on Sky1 in the UK. Kinnear's episode is expected to hit screens next year.
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