"Sharapova will carry our flag," president of the Russian Olympic Committee (ROC) Alexander Zhukov told reporters following the ROC's executive board meeting.
"She was the most worthy candidate among all our athletes. In June she claimed her fourth grand slam title (French Open)."
Russia broke with tradition by naming Sharapova, who also won Wimbledon (2004), US Open (2006) and Australian Open (2008) titles, for the rare honour.
Since the Russians first took part in the 1952 Summer Games in Helsinki as part of the Soviet Union this great honour was traditionally given to famous male athletes such as Greco-Roman wrestler Alexander Karelin and swimmer Alexander Popov, who have won numerous Olympic titles.
"I am so honoured, and especially excited as it will be my first Olympics in my career," the Florida-based Russian said on her official website when she first heard the news about her nomination last month.
"I have had to keep this hush hush for two weeks and keeping secrets is not my best quality!"
The 25-year-old will be making her Olympic debut in London after failing to qualify for the 2004 Games in Athens and missing the 2008 edition in Beijing with a shoulder injury.