Nikki Reed & Paul McDonald Perform Together in L.A.
06/07/2013 AT 06:00 AM EDT
The former Twilight actress and American Idol alum performed three co-written acoustic songs at Erik Wahl's UNthink: Rediscover Your Creative Genius book launch, where Reed couldn't keep her eyes off her man while they were on stage.
"At the event, they talked about how they have polar opposite pre-performance rituals," a partygoer tells PEOPLE. "He's a 'rock 'n' roller' who drinks whiskey. And she isn't much of a drinker, so she just meditates and takes deep breaths before going on stage."
But one thing is for sure: The pair share a mutual adoration for each other.
"They were clearly so in love," the onlooker says. "They were inseparable the whole night. She was talking about how she hates being without him. They had some PDA going on in a booth when they weren't performing."
– Dahvi Shira