Rumer Willis wore a comfy sweater and baggy pants while out on a coffee run in Los Angeles, but we couldn't help but notice the name on her cup. I guess the name "Ruby" will do!

Demi Moore and Bruce Willis' oldest daughter, wearing dark hipster glasses, is still rockin' that fiery red mane. Maybe that's where she got the inspiration for her cute nickname.

Just two weeks ago, Rumer became an older sister once again when her dad and his wife Emma Heming welcomed newborn baby girl Mabel Ray Willis.

Perhaps Ruby Rumer has been staying up late with her new sister and needed a jolt of caffeine. We have to admit, we're lovin' her casual style!