Blake Shelton shares the romantic gesture he'd do every day for Gwen Stefani

Blake Shelton is wishing girlfriend Gwen Stefani another happy trip around the sun.

Stefani turned 51 on Saturday, and Shelton wished her a happy birthday with a touching post on Instagram.

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“It’s a special day for a special lady in my life. Happy birthday @gwenstefani, I’d write a song for you every single day if I could...” he captioned a photo of himself holding a guitar in what looks like a cornfield while Stefani leans on his arm.

The “Voice” coaches, who confirmed their romance in 2015, continue to go strong and have even teamed up on a pair of duets, “Nobody But You” and “Happy Anywhere,” which they unveiled during quarantine.

Stefani and her children that she shares with ex-husband Gavin Rossdale, Kingston, 14, Zuma, 12, and Apollo, 6, spent time with Shelton while quarantining.

"It's been pretty magical for Blake and I and the kids because we don't ever have that much solid time together," she said in a clip for the upcoming season of “The Voice.” "We did do a lot of fun stuff. We did a lot of cooking."

Some other fun stuff? Stefani gave her man a mullet hairstyle and also cut and dyed his hair.

"We ordered some Just For Men and I tried that for a while, and I wasn't doing it right and it wasn't, it had too much color — it was like blue or purple or something," Shelton said last month on “The Ellen DeGeneres Show.”

"(Stefani) said, 'Let's just do it right.' And at that time I didn't care because nobody's going to see me, we were quarantined, so that was the time to mess around."