Supermodel Naomi Campbell and US singer Demi Lovato are among the many social media influencers to have turned their profile pictures various shades of blue, in a show of solidarity with pro-democracy protesters in Sudan.
Last week, dozens of protesters died in a violent crackdown at the hands of the authorities.
Blue was reportedly the favourite colour of Mohammed Hashim Mattar, 26, who was shot dead by security forces last week in the capital, Khartoum, where the protests are concentrated.
Now supporters want the colour to symbolise the wider movement.
In a separate statement of solidarity, activists in Kenya held a vigil on Thursday night for Sudan, reports the BBC 's Victor Kenani.
Earlier police had disrupted the vigil throwing tear gas into the crowd, terming the meeting as unlawful.
Some of those Victor spoke said they were there to show solidarity with the suffering of fellow Africans in Sudan.
There has been international condemnation of Sudan's Transitional Military Council (TMC), which decided last week to scrap all existing agreements with the main opposition coalition and announced plans to hold elections within nine months.
Before that point, the military and protesters agreed a three-year transition period to civilian rule.
The US assistant secretary of state for Africa, Tibor Nagy, has been trying to encourage talks between the two sides.
Similarly last week, Ethiopia's Prime Minister Abiy Ahmed held separate meetings with the TMC and the opposition, but two opposition leaders Mohamed Esmat and Ismail Jalab were arrested the next day.
The TMC had said talks would resume "soon" but these have not materialised.