The forward had 32 goals and 53 assists in 79 games and 10 points in nine postseason games and should significantly improve Russia's offense.
The Capitals made the announcement Friday, two days after the Tampa Bay Lightning swept the series against Washington 4-0. It will be Ovechkin's seventh world championship appearance for Russia.
Russia has six points in the second round of the tournament and is in good position to advance to the quarterfinals with two more games to play.
The Russian team faces defending champion Czech Republic on Sunday.