Avril Lavigne drunkenly declared her love for Brody Jenner while singing karaoke.

The singer - who filed for divorce from her husband, Sum 41 rocker Deryck Whibley, last October - has only been dating 'The Hills' actor since February but appears to be completely smitten after grabbing the microphone at the Bank nightclub in Las Vegas on Sunday night (11.04.10) and telling him she was in love.

A source told the New York Post newspaper: "Lavigne and Jenner were having a blast. They were taking shots with friends including Olympic snowboarder Shaun White, grabbing the microphone, shouting, 'Jager shots' and making the crowd go wild."

The 25-year-old pop star even shouted, "I love you, Brody!" on the microphone.

The couple - who are yet to confirm they're officially an item - then sang the Black Eyed Peas' hit single 'I Gotta Feeling' together.

As another sign of their increasing devotion, Avril and Brody recently had matching lighting bolt tattoos.

A source said: "They showed up to the opening of Mario Barth King Ink and requested the same tats. They were really excited about it. They held hands openly and were kissing in a corner. Brody didn't leave Avril's side all night."

Avril had her tattoo on her forearm, whereas Brody, 26, opted for his to be behind his ear.

Since splitting from husband Deryck - who she was married to for three years - Avril has been romantically linked with actor Wilmer Valderrama and oil heir Brandon Davis.

Brody was most recently dating Playboy playmate Jayde Nicole, but they split in December.