Beyoncé used the stage name Sasha Fierce for an alter ego during the I Am... World Tour era.
The persona was introduced prominently with the 2008 double album I Am... Sasha Fierce. Beyoncé described the Sasha Fierce side as more confident, sensual, and uninhibited than the personal side represented by the album’s “I Am...” disc. The concept gave the project a deliberate contrast between ballads and more assertive dance-oriented songs.
The album included hits such as “If I Were a Boy,” “Single Ladies (Put a Ring on It),” and “Halo.” Beyoncé later said she no longer needed to separate herself from the persona, explaining that Sasha Fierce had served its purpose in her artistic development.
Yoncé and Queen Bey are nicknames associated with Beyoncé, but they are not the same alter ego. Sasha Fierce is the specific persona linked to the 2008 album and its tour period.