Several of Ellen DeGeneres' celebrity friends have come to her defence on social media today amid allegations about the talk show host's persona and accusations about the show's working environment.

Now, DeGeneres' own family member has joined celebrities Katy Perry, Kevin Hart, and Diane Keaton in defending the star, New York Post reports.

"Okay, I need to say something. My sister is being viciously attacked. And let me assure you - it's all bulls***," DeGeneres' brother Vance wrote on Facebook.

"I put up a simple statement yesterday that said 'I stand by Ellen.' Only a handful of my Facebook 'friends' responded to it. If you don't support Ellen, then you don't support me, so please unfriend me. I'm sick and tired of my sister being attacked. She always has - and always will - stand against bullying of any kind. She's a smart, strong woman who has made a positive difference in the world. And to my friends who did respond with support for Ellen and my family, thank you so much. It means a lot."

Vance (left) pictured with Ellen and her wife Portia. Photo / Vance DeGeneres - Facebook
Vance (left) pictured with Ellen and her wife Portia. Photo / Vance DeGeneres - Facebook

The actor and comedian is Ellen's older brother, and has appeared on The Daily Show with Jon Stewart and was also an executive producer of the movie Crazy Stupid Love, according to his IMDB page.

Vance joins celebrities who have posted their public messages of support.

Actress Diane Keaton wrote on Instagram: "I always enjoyed my visits to The Ellen Show. I've seen how the audience exudes happiness and gratitude. She gives back to so many, including me."

Katy Perry took to Twitter and said: "I know I can't speak for anyone else's experience besides my own but I want to acknowledge that I have only ever had positive takeaways from my time with Ellen and on the @theellenshow," the Roar singer tweeted.

"I think we all have witnessed the light and continual fight for equality that she has brought to the world through her platform for decades. Sending you love and a hug, friend @TheEllenShow."

Comedian Kevin Hart posted a lengthy message on his Instagram page.

He wrote: "It's crazy to see my friend go thru what she's going thru publicly.

"I have known Ellen for years and I can honestly say that she's one of the dopest people on the f***ing planet. She has treated my family and my team with love and respect from day one."