Stamos vowed to be "be by your side through it all." John Stamos is showing some brotherly love to his Full House costar Dave Coulier. After Coulier revealed today that he's been diagnosed with a "very aggressive" form of cancer,

Dave Coulier has been diagnosed with cancer. The "Full House" star, 65, said he was recently diagnosed with stage 3 Non-Hodgkin lymphoma, he shared in an episode of his podcast "Full House Rewind" and in a People magazine interview published Wednesday.

As an additional tidbit for Full House fans that isn’t quite so downbeat: Dave Coulier revealed in the latest episode of Full House Rewind that he now has a new co-host in the form of fellow sitcom vet Marla Sokoloff, who famously portrayed Gia Mahan on both the mothership series and its follow-up.