His son has chosen to ride another runner but Playing God's trainer Neville Parnham is still keen on the horse's chances of an historic third win in the Kingston Town Stakes.

Parnham has the brothers Playing God and God Has Spoken in Saturday's Group One 1800m weight-for-age feature at Ascot and believes both are capable of making their presence felt in a race they will be competing in for a fourth time.

Steven Parnham is the regular rider of Playing God but will be aboard three-year-old WA Guineas winner Ihtsahymn for trainer Fred Kersley.

Playing God won in 2010 and 2011 and was sixth last year, while his elder brother God Has Spoken was runner-up as a three-year-old in 2009, eighth in 2010 and third last year.

"It was a pretty tough decision for Steven. He chose the other horse because of the seven kilo pull in the weights and the horse seemed to have improved out of the Guineas," Neville Parnham said.

Paul Harvey takes the ride on Playing God while Parnham's other jockey son Brad partners God Has Spoken.

Playing God, who is striving to become the first horse to win the Kingston Town three times, is at $9 while God Has Spoken is at $26.

Luckygray is the $2.50 favourite ahead of Ihtsahymn at $4.20.

Parnham said there hadn't been a lot between Playing God and God Has Spoken in the past 12 months and was confident both would run well in what he believes will be a tricky race without a lot of speed.

The trainer said God Has Spoken had been overshadowed by his younger brother.

"He has won a Cox Stakes and won several feature races and also placed in lots, but his brother overshadows him a bit because he's won two Group Ones," Parnham said.

"In a way I'd be happy if he (God Has Spoken) won, but by the same token it would be quite a feat for one horse like Playing God to win the race three times.

"I'd be pretty chuffed if either of them could salute because they have been great for the stable and they are in their twilight years.

"They are going to be hard to replace."