The singer posted a heartfelt note on Instagram to celebrate her husband's special day.
Lambert shared a picture of her kissing him on the head, with the former NYPD cop smiling big. More pictures she shared included him with animals and the two driving in a car together.
"Happy Birthday to my sweet husband," she wrote. "The man I love so much with the most contagious smile. Brendan you are a light. ❤️ (and I love your obsession with cows🐄) #nyc #dreamboat."
Last February, Lambert revealed she and McLoughlin secretly tied the knot after a whirlwind romance. In July, she talked about quarantining with McLoughlin due to the coronavirus as newlyweds.
"If newlyweds can survive a pandemic then I think we're good, you know? It's a good test," she told Kelly Ford of New York’s Country 94.7. "The first month I had a lot of fun. Well, not fun but I was like, 'OK, we're off. We'll probably be back on the road in a couple of months.' I cooked too much and ate way too much, and then I had to roll that back a little bit. There's stuff to do, it's just the adjusting of not knowing when I'm going to work again... it's uneasy."
Meanwhile, ET spoke with Lambert last November, and she talked about the joy her husband has brought into her life.
"It's really good to be genuinely happy," she said. "You almost don't realize that you're not until you get there and you're like, ‘Man, I didn't know that there was a level of comfort and happiness out there that existed like that.'"
"He's a really positive, upbeat person, so that's good for me because I tend to lean negative -- we Scorpios do -- so we're a good balance,” she added. "He keeps me in check. He's just normal and cool and always smiling. [When] someone’s that happy, there's no choice but to [be happy too] and it's really great."