Kristin Cavallari gives first glimpse of baby daughter Saylor James

Kristin Cavallari had a valid excuse for missing her ten-year high school reunion on Saturday. The 28-year-old opted for a night in with her baby girl Saylor James, who she welcomed with husband Jay Cutler on Monday 23 November.

The proud mum shared her first glimpse at the newborn in an Instagram photo on Sunday, as she revealed she was "really sad" about missing the reunion the night before. The image showed baby Saylor wrapped up in a pink blanket as she slept peacefully in her mother's arms.

Kristin gave her first glimpse at her baby daughter Saylor James

"Really sad about missing my 10 year high school reunion last night… so many people I wanted to see… but at least I have a good excuse," she wrote.

Kristin announced the happy news that she had given birth to a baby daughter on the social media site on Monday, writing: "Saylor James Cutler was born today at 132pm!!"

Baby Saylor joins big brothers Camden Jack, three, and one-year-old Jaxon Wyatt.

Saylor James Cutler was born today at 132pm!! 🎀💕

A photo posted by Kristin Cavallari (@kristincavallari) on

Saylor James is Kristin's third child with husband Jay Cutler

"Kristin and Jay are so happy!" a source told E! News after the birth. "They were surrounded by friends and family. Kristin is so thrilled to welcome her new baby girl to her family! Jaxon and Camden are excited to be older brothers. She is feeling great!"

The 28-year-old announced that she was expecting her third child in May. "We're at it again!" she told fans. "Thrilled to announce baby number 3 is on the way! The Cutler crew just keeps on growin'!"

Two months later the reality TV star revealed that she was expecting a baby girl, sharing a sweet photo that showed her holding a tiny pair of pink Converse trainers, resting her arms on Jay's shoulders as they look into each other's eyes.

Kristin and Jay started dating in late 2010 and got engaged in April 2011. They briefly split up that same year, but reconciled in November and were married in June 2013 in Nashville, Tennessee. The couple had Camden Jack in August 2012, and little brother Jaxon in May 2014.