Martin, who famously "consciously uncoupled" from his ex-wife Gwyneth Paltrow, has been in London this summer with a string of Wembley dates as part of Coldplay's Music Of The Spheres tour.
Turner, 29, who was previously married to Joe Jonas, is a big Coldplay fan, having received a special birthday message from the singer, which was organized by her ex-husband.
In the video, which was taken in 2020 from Jonas's show Cup of Joe, Turner was surprised for her birthday by her ex-husband, 36, with a video of her new love interest.
Sitting in a restaurant, Jonas passed the actress his phone, explaining, "I have someone who wants to say happy birthday.