The daughter of Kodiac, who finished fifth in the Albany Stakes at Royal Ascot, will bid to give her Newmarket handler a first win in the six-furlong Group Two by backing up her recent Listed success at Newbury over the same trip.
"She is in great form and has done nothing but impress us all year and she goes to the Lowther as a very lively contender. She is versatile ground-wise, as she will be fine if the ground was good to firm or good to soft," said Varian.
"The form of the Albany is very strong and is probably as good two-year-old fillies' form as there has been all year. The winner Different League ran very well in the Morny on Sunday and several winners have come out of the race.
"She is a good filly and deserves to be near the head of the market."
Aidan O'Brien holds no reservations about turning Actress out less than two weeks after finishing third behind stablemate Sioux Nation in the Phoenix Stakes at the Curragh.
He said: "She has been progressing with every run. Obviously we're going back a little bit early with her, but she's in good form. She came out of her last race well and we're hoping she runs well."
Archie Watson will have been delighted to see the rain that hit the Knavesmire before racing on Wednesday as he prepares to saddle So Hi Society, who is dropping back down in trip.
He said: "She is quite ground-dependent and probably wants a bit of cut in the ground. She is in great order at home and her work has been very good. She has had a little break since Sandown and more than deserves a place in the race.
"She probably stays seven, but it was a stiff seven at Sandown and they got racing quite far out. She shows plenty of boot at home and six is probably her trip."
Connections of the Mark Johnston-trained Threading are optimistic she can take the step up in class and justify the decision to supplement her after an impressive debut win at Goodwood.
Assistant trainer Charlie Johnston said: "Threading was supplemented for the Lowther at a cost of £15,000 last Friday. It is obviously a big step up, but she was very impressive at Goodwood. Not many fillies win a Glorious Goodwood maiden by six lengths.
"She is a filly we have always liked and we feel she is up to being competitive at this grade. It looks a wide-open Lowther and one we feel she has a chance of running very well in."
The Wesley Ward-trained Happy Like A Fool, who was a late withdrawal from the Molecomb Stakes at Goodwood due to the soft ground, will look to bounce back from her odds-on reversal in the Queen Mary at Royal Ascot on her first try over the trip.
Special Purpose, one of two runners for Qatar Racing alongside the Richard Hannon-trained Natural, will attempt to take her record to three from three for trainer William Haggas.
The field is completed by Neola from the yard of Mick Channon and the Ken Condon-trained Mambo Noire.