Lured by proximity to its prominent media clients — and sky-high views — hot cross-platform digital branding firm Undertone is leaving Midtown for One World Trade Center.

Undertone, a leader in digital marketing that’s currently based at 340 Madison Ave., has signed a lease for 25,550 square feet on the 77th floor of the iconic tower owned by the Port Authority and the Durst Organization.

The move is planned for January. Undertone president Michael Pallad said the investment in the relocation “showcases our commitment to our clients.”

Pallad told The Post that although Undertone checked out Hudson Yards and Midtown and Midtown South locations, “For us, the decision [to choose 1 WTC] was simple. All of our clients in digital media continue to move down there” — i.e., to the World Trade Center, Brookfield Place and a few other nearby sites. They include WPP and Omnicom on the agency side, and Condé Nast and Meredith on the publishing side, he said.

Another benefit is an easier commute for Undertone’s employees, most of whom live in Brooklyn or nearby downtown.

Undertone, a division of Nasdaq-traded Perion Network, is 17 years old — “a lifetime in digital marketing,” Pallad said, chuckling. It’s poised to expand its workforce by up to 65 percent, he said. The ultra-modern, open-plan space high up at 1 WTC can accommodate the growth. The firm also has first-refusal rights for additional space on the same floor, he said.

Undertone’s collaborative-minded space will be designed by Forge architect Amy Howell.

The Undertone deal brings office leasing at One World Trade up to a hair shy of 80 percent, a Durst rep said. The asking rent was $69 a square foot. JLL’s Paul Ferraro and Deborah van der Heyden repped Undertone. Ownership was repped by Durst’s Eric Engelhardt and a Cushman & Wakefield team led by Tara Stacom.