Katy Perry and John Mayer Show PDA at Saturday Night Live After Party

Katy Perry had a roar-ing good time with beau John Mayer Saturday night. After performing as Saturday Night Live's musical guest on Oct. 12, the songstress had a PDA-filled night with Mayer at the show's after party.

"[They] were beyond affectionate and adorable," a source reveals to Us Weekly. While enjoying the night at Heartland Brewery alongside other A-listers like Bruce Willis, Lorne Michaels and BJ Novak, the couple stayed close as they ordered food and were later spotted at one of the back tables.

"He was rubbing her back, then pulled her in for an intimate close chat," the eyewitness adds. "She put her hand inside his jacket and they were kissing and gazing into each other's eyes."

The couple split briefly as Perry talked with her entourage -- dancers, hair and makeup friends -- and Mayer chatted with Novak. The pair then met back up and stayed together for the rest of the night before heading out at 3 a.m.

Earlier in the night, the 28-year-old Prism singer took the SNL stage to perform her hit track "Roar" and "Walking on Air."