Robbie Dunne and Bryony Frost compete against each other at Ludlow on Thursday.
The pair, at the centre of a British Horseracing Authority investigation which has rocked the sport, have a ride booked in the first race on the card.
Dunne, whose behaviour towards his weighing room colleague is the focus of the probe, will be aboard Cup Of Coffee in the Suzuki ATV Mares' 'National Hunt' Maiden Hurdle.
On the forecast betting odds, the pair have work to do to beat the expected favourite, Frost's mount Rainyday Woman, trained by 12-times champion Paul Nicholls.
The race, run over almost two miles, comes just days after Frost teamed up with the same stable's top performer Frodon to win the Grade 1 Ladbrokes Champion Chase at Down Royal.
In 2019, the star chaser enabled her to become the first female jockey to take a top level race at the Cheltenham Festival.
Frost's achievements come amid claims about Dunne's behaviour towards her, which became public knowledge in recent weeks.
A leaked 120-page report, from the British Horseracing Authority, makes allegations including Dunne swearing at Frost pulling up after a race.
Frost first revealed the difficulties she was facing in December after winning the King George VI Chase on Frodon having lodged a complaint with the BHA.
Dunne denies the allegations, while the Professional Jockeys' Association has called for the matter to be brought to an end, suggesting that a "fair hearing is impossible," following the report leak.
First published in The Sunday Times, it claimed Dunne was charged with "conduct prejudicial to the integrity or good reputation" of racing.
The 42-year-old jumps jockey from Ireland, whose biggest success came in the 2015 Scottish Grand National, has not raced since a fall in August.
He was due to return at Musselburgh today, however his horse was pulled out of its intended race.
Frost, 26, has had four winners from her last eight rides on the track.
The British Horseracing Authority said two and a half weeks ago that the bullying claims case was close to reaching a conclusion.
A spokesman stated that there was nothing further to add at this stage.
