Have pop star and activist Lady Gaga and actor-model Taylor Kinney ended their engagement?

TMZ.com on Tuesday posted a photograph of Grammy Award-winner Gaga, 30, on vacation in Cabo San Lucas, Mexico, last week, stepping out of a large red vehicle, noticeably absent the heart-shaped, diamond-encrusted engagement ring she had displayed on Instagram in February 2015. At that time, she wrote, “He gave me his heart on Valentine’s Day, and I said YES!”

The website noted that the couple has not been seen together recently at events or on social media, and that the photo sans ring was taken on July 15, Kinney’s 35th birthday.

Representatives for Gaga and Kinney did not immediately respond to Newsday requests for comment.

Gaga and Kinney, who stars as Lt. Kelly Severide on NBC’s “Chicago Fire,” had met in 2011 on the set of her “You & I” music video, in which he played her paramour. Months later they began dating, and after a brief breakup in May 2012 were together again.

Engagement rumors began circulating following Gaga’s Christmas Day tweet, “Merry Christmas monsters, today has been the happiest day of my life. Have a peaceful and healthy holiday.”