The video of the Times Square bomber, which confirms his earlier claim that he had met Mehsud and other radical leaders, is now on Sky News website.
"Today, along with the leader of Tehrik-e-Taliban Pakistan Hakimullah Mehsud and under the command of Amir al-Mumineen Mullah Mohammed Omar Mujahid (may Allah protect him), we are planning to wage an attack on your side, inshallah," Shahzad is heard saying.
Shahzad has already pleaded guilty of trying to detonate a car bomb in crowded Times Square on May 1, 2010.
The 30-year-old Pakistan-born American had admitted that he had asked the Taliban for some cash because he only had 4,500 dollars when he was leaving.
"And I asked for some more cash because I had to do the whole operation here," he told the US court.
Lask week, the traditional "testament" video, a footage made generally by suicide bombers before attacks, of Faisal Shahzad was released by Al Arabiya television.
In the video a man wearing traditional tribal clothes and sitting with an assault rifle, believed to be Shahzad, says, "This attack on the United States will also be a revenge attack for all the mujahideen."