Katy Perry & Russell Brand: Grandma's 90th Birthday in Vegas!

Katy Perry and Russell Brand sandwich in her grandmother, Ann Hudson, at Planet Hollywood Resort & Casino on Wednesday (January 12) in Las Vegas.

The couple helped Ann celebrate a milestone b-day at Strip House.

“Happy 90th birthday grandma HUDSON! You’re the reason why!” Katy, who wore an Asos dress and Casadei leather pumps, tweeted.

FYI: Katy is set to perform at this year’s Grammy Awards, according to ET.

The 26-year-old singer, who’s nominated for four Grammys, including Album of the Year, will hit the stage at the show on February 13!