Contracts have not been signed, but UFC is close to finalizing the 185-pound bout. The UFC Fight Night event is scheduled to take place at 3Arena in Dublin.
Whittaker (20-5) has not fought since he surrendered his title to current champion Israel Adesanya at UFC 243 in October in Melbourne, Australia. The Sydney-based middleweight was initially set to return to the Octagon last weekend at UFC 248 opposite Jared Cannonier, but was forced to withdraw for undisclosed reasons.
Prior to his loss to Adesanya, Whittaker had won nine in a row, including back-to-back five-round decisions over Yoel Romero.
Till (18-2-1) is coming off a split-decision victory over Kelvin Gastelum at UFC 244 in November. It was the former welterweight title challenger's middleweight debut in UFC. Fighting out of Liverpool, England, Till challenged Tyron Woodley for the 170-pound championship in September 2018 and lost via submission in the second round.
Whitaker and Till are the Nos. 2 and 6 middleweights in the world, respectively, according to ESPN.
The Aug. 15 event will mark UFC's first trip to Ireland since November 2016. Irish superstar Conor McGregor is not expected to compete on the card.