Along with holding up the handwritten sign with the phrase, Remigio Pereira reworded two lines of "O Canada" to include the words, which are regarded as a counterargument to the Black Lives Matter movement, according to CNN partner CBC.
In place of the lines "With glowing hearts we see thee rise/The True North strong and free," he sang: "We're all brothers and sisters/All lives matter to the great."
Pereira, a member of the Juno Award-winnning group The Tenors
, appears to have acted alone after the quartet released a statement disavowing his actions.
Calling the singer a "lone wolf," the statement expressed remorse for his actions and added that the other members of the group were "shocked and embarrassed" that Pereira used the "coveted platform" of the All-Star Game to "serve his own political views" with the "shameful" act.
It added that he will not be performing with the group "until further notice."
The phrase is used by opponents of Black Lives Matter to argue that the movement's claim excludes the sanctity of the lives of other races.
Proponents of the movement say that that argument misses the point of Black Lives Matter -- that by highlighting the disproportionate number of African-American men's deaths at the hands of law enforcement only serves to highlight the apparent disregard for black lives, not claim that black lives take precedence.
The loaded phrases have become more heated in the wake of the latest high-profile killings of black men by police officers.
was shot by police in Falcon Heights, outside Minneapolis on Wednesday after being "pulled over for a busted tail light," according to a woman identifying herself as his girlfriend.
, known as the "CD man," sold CDs and DVDs outside a convenience store in Baton Rouge, Louisiana -- where he was killed by police on Tuesday.
The killings sparked protests around the country, and spurred the killing of five Dallas police officers, shot during a Black Lives Matter protest.
Former New York Mayor Rudy Giuliani told Fox News earlier this week that the Black Lives Matter movement is "inherently racist
"It's inherently racist because, number one, it divides us," he said "All lives matter: White lives, black lives, all lives."
Meanwhile, in Minnesota, four off-duty cops walked from their security duties after Minnesota Lynx players wore Black Lives Matter shirts
during a warm-up before a game.
The anthem wasn't featured on the U.S. broadcast of the game, but Canadian viewers heard it, sparking a backlash online.
One user, Morgan Campbell, apparently unaware that the change was not officially sanctioned, suggested to the MLB that "all lives mattering" the anthem would alienate black fans.
Others reacted angrily, with one suggesting that the politcially-charged message was "grounds for deportation."
Another user, also unaware that Pereira had acted alone, said that the group should keep their "political statements" separate from the anthem.
Canadian user Harrison Mooney said that, while the group used to be called "The Canadian Tenors," the name did not mean that the group spoke on behalf of all Canadians.
The American League All-Stars beat the National League side 4-2 in the game.