One World Trade Center has signed its first new lease in nearly three years, The Post has learned.

KiDS Creative, an advertising agency offshoot of premier digital artistry shop Box Studios, has taken the tower’s entire 87th floor, with just under 35,000 square feet.

Box Studios and KiDS were both founded by photo-imaging wizard Pascal Dangin, who describes Box as “a finishing house devoted to the image.”

Sources said the long-term lease was done for over $90 a square foot.

Both the lease and the cost come as a surprise. In Tuesday’s Wall Street Journal, Douglas Durst, who’s partners with the Port Authority in 1 WTC, suggested that leasing has become so quiet, he’s had to reduce asking rents to $69 a square foot in the tower’s middle floors.

“The market’s not there,” Durst told the Journal.

A Durst rep clarified to us that above the 64th-floor “sky lobby” level, asking rents are $80 to $100 a foot.

Durst Organization leasing director Eric Engelhardt said, “KiDS is ‘best in class’ in the world of digital artistry and creative design, while 1 World Trade Center is the world’s most prestigious business address.”

Engelhardt said the 87th floor setting “will be a coveted work environment” and “serves as an ideal complement to Conde Nast,” the tower’s largest tenant with over 1.1 million square feet.

Box Studios, based on West 14th Street, specializes in fashion branding for such lines as Dolce & Gabbana and Alexander Wang.

A statement from KiDS Creative was expected later Tuesday. Cushman & Wakefield’s Tara Stacom, the leasing agent for 1 WTC, was traveling and could not immediately be reached.

PA rep Anthony Hayes called the news “further proof that One World Trade Center will serve as a center for jobs and commerce in our region.”

Although for only a single floor, the KiDS deal is a breakthrough. It signifies the strong demand by media, digital and tech firms for space at the new WTC and at other modern office buildings nearby.

The Post reported last week that tech firm Percolate is in advanced talks for around 40,000 square feet at 1 WTC, while Hugo Boss is in more preliminary talks for a much larger block.

Meanwhile, digital firm MediaMath is close to finishing a lease for 140,000 square feet at Larry Silverstein’s 4 WTC.

On Wednesday, the PA is expected to vote on Silverstein’s request for a construction-loan guarantee to build 3 WTC, which is stalled at the 7th floor level. Media giant GroupM has already signed a lease there for 350,000 square feet.

One WTC’s nearly 3 million square feet are over 55 percent leased with deals in place for Conde Nast, Beijing Vantone and the US General Services Administration.