However, in the tweet, Nehlen replaced Markle's face with a photo of Cheddar Man, an ancient man rendered from the DNA of a fossil found in the village of Cheddar in southwest England.
With the Cheddar Man a hot topic in social media, Nehlen jumped on the subject with disastrous results.
Markle's Suits co-star Patrick J. Adams came to his colleague's defense, calling the politician "sad and sick" for his actions.
"Get a life. And don't go anywhere near MM - she's got more power, strength, honour and compassion in her fingernail than you'll ever know in this lifetime. Way above your weight class".
Meanwhile, Markle and Adams became close friends after playing love interests Rachel Zane and Mike Ross on hit USA legal drama Suits.
The supporter tweeted the image, which also featured Prince Harry, with the caption: 'Honey, does this tie make my face look pale?'
In a Tweet Sunday linking to a report by British tabloid the Daily Mirror, Nehlen defended the posting.
Twitter users lined up to condemn Nehlen, who refused to delete the shocking image.
Nehlen has been described by the Southern Poverty Law Center as "a defiant mouthpiece for the racist "alt-right", and in Janaury was suspended from Twitter for a week for violating rules banning anti-Semitic content.
The reason for the suspension is now unclear, and Nehlen has not yet spoken out about it on Facebook, his other primary means of communication.
Paul Nehlen, a Republican challenger to House Speaker Paul Ryan, has been suspended from Twitter. The GOP candidate is running for Congress to replace United States speaker Paul Ryan in his Wisconsin district.
Speaking about leaving her acting career behind her, in her first joint TV interview with Prince Harry, Meghan said: "I don't see it as giving anything up, I just see it as a change..."