Promising filly Acting will be a late entry for the Group One Thousand Guineas after delivering a star performance to win the Prelude at Caulfield.

Acting had won her past two starts at Echuca and Sandown and made the step up to stakes grade in Sunday's Group Two Thousand Guineas Prelude, leading throughout in the 1400m-race.

The Trent Busuttin and Natalie Young-trained filly, ridden by visiting Sydney jockey Tommy Berry, started at $21 and controlled the race to beat Southbank by 1-1/2-lengths with a short-head to Barbie's Fox third.

The $3.20 favourite Flit finished ninth but was unable to get clear running in the home straight.

Busuttin said it was an administrative error that Acting was not initially entered for the Thousand Guineas but confirmed the intention to pay up as a late nomination.

The late entry is $27,000 for the $1 million 1600m-race for fillies on October 12.

"It was an oversight for sure," Busuttin said.

"I was notified two days later that she wasn't in there.

"It's a $27,000 error."

Acting's victory in the Prelude came as no surprise to Busuttin, who trains in partnership with Natalie Young.

"I thought that's what she would do, to be honest," Busuttin said.

"She's a fantastic filly.

"You never say 'I told you so', but this is the best horse in our stable."

Acting, by Savabeel out of Hollywood, races in the colours of New Zealand's Waikato Stud.

"Obviously it's great to get a Group Two for them and we'll be back here in two weeks for the Group One," Busuttin said.

Acting will need a new jockey with Tommy Berry to miss riding on October 12 after receiving a suspension for overuse of the whip at Rosehill on Saturday.