Los Angeles, March 6 (IANS) Singer Britney Spears celebrated her beau and personal trainer Sam Asgharis birthday by spending some quality time together.Asghari turned 23 on March 3. Spears, 35, took to Instagram to greet him, reports aceshowbiz.com.She shared three photographs from the celebration."My baby's birthday Sam Asghari," Spears wrote alongside the images.The first photograph showed the couple on a hike together. Spears also presented a special cake to her beau by writing his real name Hesam on it. The couple then posed for a Snapchat selfie. Asghari, meanwhile, posted an image of his birthday cake from Spears. He wrote alongside the image: "She calls me by my real name".