SINGER Ariana Grande has struck a bum note over her "disrespectful" skimpy minidress choice for Aretha Franklin's funeral - but one man certainly wasn't complaining.

Former US president Bill Clinton has been accused of being "mesmerized" by the 25-year-old as she belted out a tribute song during the Queen of Soul's star-studded service.

As she sang the Aretha hit '(You Make Me Feel Like) A Natural Woman', Clinton was seen staring intently at her from his seat next to Reverend Jesse Jackson.

Outspoken US journalist Alex Jones was among those to have a pop at Clinton, who was infamously impeached for lying over his relationship with White House intern Monica Lewinsky.

He tweeted: "Clinton appeared mesmerized by vocalist Ariana Grande's rear end."

"Gross... Watch Bill Clinton look Ariana Grande up and down when she sings at #ArethaFranklinFuneral and try not to throw up in your mouth," added comedian Tim Young.

Other Twitter users took aim at the 'God is a Woman' star over her barely-there black dress and high heels with many saying they were not fit for the occasion.

"Arianagrande that dress in front of all the seniors though.. My grandma would have whooped my ass while the congregation watches," one wrote.

"Ariana Grande's dress totally inappropriate and bending over..." added a second while one joked that Clinton was "just about to have a heart attack when he saw that tiny dress."

"Loved Ariana Grande at the same time that dress was very inappropriate I'm sorry," another wrote.

Many felt that the choice of fashion was not traditional with the etiquette that accompanies African-American services.

"#ArianaGrande don't know the below the knee rule for the pulpit in the black church. Somebody hand her a lap hanky and a choir robe. Bless her heart," tweeted Tenisha Taylor Bell.

"I can't believe she came in a black church for a black funeral dressed like this," said comedian and writer Crissle West.

Meanwhile the bishop who officiated the seven-hour funeral has now apologised to Ariana for how he touched her on stage and joked about her name.

Bishop Charles H. Ellis III led Franklin's funeral and awkwardly greeted Ariana on stage after her performance.

Pictures showed Ellis' hand holding the chart star well above her waist, with his fingers pressing against one side of her chest.

He later said sorry in an interview with The Associated Press at the cemetery where Franklin was interred late Friday.

"It would never be my intention to touch any woman's breast... I don't know I guess I put my arm around her," Ellis said.

"Maybe I crossed the border, maybe I was too friendly or familiar but again, I apologise."

He said he hugged all the performers during Friday's funeral service.

"I hug all the female artists and the male artists,' Ellis said. "Everybody that was up, I shook their hands and hugged them. That's what we are all about in the church. We are all about love."

He added: "The last thing I want to do is to be a distraction to this day. This is all about Aretha Franklin."

Many people posted close-up images of the moment on Twitter, tagging it #RespectAriana.

Ellis also apologised to Grande, her fans and Hispanic community for making a joke about seeing her name on the funeral programme and thinking it was a new item on the Taco Bell menu.

Eaarlier Clinton described himself as an Aretha "groupie," saying he had loved her since college.

He said he and wife Hillary, who attended the funeral with him, had long been avid fans of the soul singer.

'We started out not as President and First Lady, but as Aretha groupies or something,' he joked.

He traced her life's journey, praising her as someone who "lived with courage, not without fear, but overcoming her fears".

He remembered attending her last public performance, at Elton John's AIDS Foundation benefit in November in New York.

She looked "desperately ill" but managed to greet him by standing and saying, "How you doing, baby?"

Her career, Clinton noted, spanned from vinyl records to cellphones.

He held the microphone near his iPhone and played a snippet of Franklin's classic "Think," the audience clapping along. "It's the key to freedom!" Clinton said.