A newly renovated Upper East Side townhouse just sold for $25.25 million.

The buyer is shielded behind an LLC, but it appears to the successful female founder of a high-profile fashion retail website.

The two-building property first went on the market for $29.25 million earlier this year.

The 12,000-square-foot landmarked home at 134-136 E. 74th St. was built in 1870.

Developers Ivan Hakimian and Larry Gluck bought the home for $12 million in 2009 in an off-market deal.

The developers had a tenant — an ex-hedge funder turned art dealer — who stayed for around five years.

They started the gut renovation, transforming the two-building home into a single-family mansion in 2015.

The renovation is about 80 percent complete — and it will be completed by the buyer to her specifications.

It closed before the mansion tax went into effect July 1.