“Happy ❤️ day! #love” the country star, 36, captioned the sweet selfie.
The couple, who announced their union in February 2019, celebrated their first year of marriage late last month.
“1 year ❤️. I’m so happy to walk through this life with you,” Lambert wrote in a touching social media tribute, which she shared alongside a photo of the couple walking hand-in-hand on their wedding day.
“Thank you Brendan for making me the proudest wife and stepmom. You are the reason for all my new smile lines. I love you,” she added, including the hashtag “Mrs. McLoughlin.”
The singer, who kicked off her Wildcard tour earlier this year, previously told PEOPLE she fell fast and hard for 28-year-old McLoughlin, whom she met outside of Good Morning America in November 2018 while visiting the show to promote new music with the Pistol Annies.
“I feel like I’ve been through enough in my life to know what I don’t want, so when I know what I do want I snatch it right up,” she said.
Lambert also shared that her native New Yorker husband, who is a NYPD officer, has opened her “eyes to a whole new world” with city living.
“My husband is very open and happy to travel and could be ready to go anywhere in 15 minutes,” she said of McLoughlin, who has joined her on the road working security after taking leave from the police force.
“I love that. Kind of met a kindred spirit there,” Lambert added.
RELATED VIDEO: Miranda Lambert Reveals the Real Reason Behind Her Secret Wedding: ‘It’s Not for Everybody
Three months after meeting McLoughlin, Lambert revealed on social media that they had tied the knot in secret on Jan. 26, 2019 at a farm just outside of Nashville.
As for why they chose to keep their happy day under wraps, she said the decision was a no-brainer, especially after the scrutiny her love life has received over the years.
“I was married before, and it was a huge wedding and everything was very public. So was my divorce,” Lambert said of her previous marriage to ex-husband Blake Shelton, which lasted from 2011-2015. “I learned then that it’s not for everybody else. This is my actual life. With Brendan, I made it a point to keep it as private as I could for as long as I could.”