American Romanchuk won the Boston, London, Chicago and New York Marathons last year, with his dominance resulting in the World Marathon Majors title.

Only Switzerland's Marcel Hug has defeated Romanchuk in the past 18 months, triumphing at the Tokyo Marathon.

Hug is set to compete in London on October 4, alongside Britain's eight-time London Marathon champion David Weir and this year's Tokyo Marathon champion Sho Watanabe.

In the women’s field, Switzerland's Schär will be aiming for yet another victory.

The 35-year-old had won nine World Marathon Major races in a row, before missing the Tokyo Marathon in March. 

Two-time London Marathon champion, British record holder and London 2012 Paralympic silver medallist Shelly Woods is set to make her return to competition after a four-year absence, during which she had a son.

"This is an incredible line-up for what will be a unique Virgin Money London Marathon on Sunday 4 October," Hugh Brasher, London Marathon event director, said.

"Wheelchair racing on a closed-loop course around St James’s Park is an amazing spectacle and with the very best athletes on the planet coming to London to compete, it promises to be one we will never forget."

This year's London Marathon will only feature elite races due to the coronavirus pandemic. 

The event had been rescheduled from April to October, before it was decided that mass participation would not be possible. 

The wheelchair races, along with elite men’s and women’s contests, will be held in bio-secure conditions with no spectators.