Jepsen, the Canadian pop singer best known for the inescapable hit "Call Me Maybe," made the announcement Tuesday on Twitter.
"I always have and will continue to support the LGBT community on a global level," she wrote, "... and stay informed on the ever changing landscape in the ongoing battle for gay rights in this country and across the globe."
Rock band Train also has taken a stand, but pursued a different tack in a post on its website Friday. The group asked the BSA to reconsider its policy rather than immediately pull out of the July gathering in West Virginia. The event, held once every four years, is expected to draw more than 45,000 scouts and adults.
Members of Train said Friday in a message on their website that they were unaware of the policy barring gay scouts and adult leaders from participating in the organization before agreeing to perform.
"Train strongly opposes any kind of policy that questions the equality of any American citizen," the statement said. "We have always seen the BSA as a great and noble organization. We look forward to participating in the Jamboree this summer, as long as they make the right decision before then."
Deron Smith, publicity director for the BSA, says the organization is moving forward with plans for the Jamboree.
"We appreciate everyone's right to express an opinion and remain focused on delivering a great Jamboree program for our Scouts," Smith wrote in an email. Smith was unaware of any other performers scheduled to participate in the event.
The BSA's policy has drawn attention before and gay rights organizations hailed Jepsen and members of Train for taking a stand and helping to bring the issue back into the public debate.
"Carly Rae Jepsen and Train's decisions not only send the right message to the BSA, but remind LGBT young people that they are supported and accepted," said Rich Ferraro, GLAAD's vice president of communications, in a statement.
Ferraro said in an email that Jepsen and Train were alerted to the Boy Scouts' regulation through the efforts of Eagle Scout Derek Nance, whose petition at change.org asked them to change their mind about playing the jamboree. Nance, who says he is gay, gathered 62,000 signatures, each of which spurred an email to the artists' management.