Kathy Griffin has branded Roseanne Barr ''a Nazi''.

The 57-year-old comedienne claims the 65-year-old actress - who recently came under fire for making a racist remark on social media about former White House adviser Valerie Jarrett - has had ''Nazi leanings'' and retweeted messages from people who follow the ideology ''for years''.

She said: ''The talk of a double standard is all propaganda.

''The truth is, Roseanne has displayed herself to be a Nazi.

''She has Nazi leanings; she retweets Nazis. She's been doing this for years. She is someone who tweets things that are conspiracy theories that lunatics then act on, like 'Pizzagate.'

''There's a big difference between someone using the C-word and what Roseanne was doing.

''There's a very clear delineation between Republicans who didn't like Hillary [Clinton] and people who know that by pushing certain conspiracies, it leads to acts of violence.''

Kathy credits Roseanne with helping her to get a job on sketch series 'Saturday Night Special' - which the star produced - and admits the 'Teenage Mutant Ninja Turtles' actress' recently controversial comments did not come from the Roseanne she knows.

Speaking about the last time she saw Roseanne with her then-boyfriend Johnny Argent during a lunch nearly a decade ago, she added to USA Today: ''I've known a lovely Roseanne.

''She said, 'We're just a couple of old hippies.' And I'm like, 'Do you believe in equal rights? Because if that's what makes you an old hippie, that's fine. I'm in.'

''So not only is this not the Roseanne that I knew - I didn't see this coming at all until years later when every so often, somebody would say, 'Roseanne's tweeting crazy [expletive].' ''

Following Roseanne's controversial comment - in which she likened Valerie, a former aide of Barack Obama, to an ape and accused her of supporting the Muslim Brotherhood political party - she has since vowed to make amends.

She tweeted: ''I'm making restitution for the pain I have caused.''

Following the tweet, Roseanne's eponymous sitcom was cancelled by US TV network ABC.