Yupun is to compete in the mens' 100m event while Nilani will compete at the 3,000m steeplechase event.
Yupun is an Italian-based Sri Lankan track and field athlete and a national record holder in men's 100m and in men's indoor 60m.
He reached his career-best world ranking of 48 following a fourth-place finish in the men's 100 event at the Golden Gala as part of the 2021 Diamond League Meet at Florence. He also became the first Sri Lankan to compete at the Diamond League.
Nilani holds the Sri Lanka record of the Steeple Chase which she set in 2018 for the second time.