The number of stars joining Billboard magazine's petition against gun violence now reaches to 133, thanks to latest additions Katy Perry and Taylor Swift.

More familiar faces are even expected to come in and join in the solidification of the petition.

The front-liners of the signers' list include Adam Lambert, Alicia Keys, Barbra Streisand, Calvin Harris, Cher, Ellen DeGeneres, Elvis Costello, Jennifer Lopez, Lee Daniels, Meghan Trainor, Paul McCartney, Ringo Starr, Selena Gomez, Tony Bennett, Yoko Ono and many others, Yahoo reported.

Meanwhile, the anti-gun violence petition by the Brady campaign is a closely-related act which has also been drawing out attention from the U.S. policy-makers with a muscle.

Like the petition mentioned earlier, this petition obviously seeks to mitigate further gun-ownership-related crimes in America.

The group had started flinging out an earlier anti-violence project called the "Zero Minutes of Fame" last April this year and had since gone stronger with the affixed popular anti-gun violence petition.

What bolstered this out was presumably the alarming terrorist attack in Orlando, Reuters reported.  

Back to the celebrity fiesta- The Billboard magazine-organized petition emerges as the most immediate response to the Orlando shooting.

Originally called forth by the named celebrities themselves, the petition has instantly gone out viral in Twitter, Facebook and many other social media sites.

But what compelled these celebrities most was Orlando's twin tragedy involving celebrity Christina Grimmie.

The letter's content inside the petition expresses the fear that is presently blanketing the music industry in the U.S. and a list of how the Congress can do better in preventing gun-related violence in the future. In a moving art, the letter finishes with lines from famous songs, past-present.

On the other end, the Brady campaign group expresses sincere desire to partner with the on-going petition by the Billboard magazine, Reuters  again reported.

As predicted later today, a longer line along the hall of fame will definitely fill the tinsel town. A bigger surge of celebrities will soon be appearing to sign on the expanding petition, WENN reported.