The loved-up couple hit the trails on horseback and personal trainer Sam shared a video of the canter on Instagram.

"Happy Asheghetam Day," he wrote. "Happy 4th valentine together my lioness @britneyspears."

Sam and Britney weren't the only stars celebrating the most romantic day of the year on social media - Tom Brady and his wife Giselle Bundchen posted shots of themselves kissing and snuggling and there were also photo tributes to their loved ones posted by Joe Jonas, John Legend, Shania Twain, Miranda Lambert, and Justin Timberlake.

Meanwhile, Paul McCartney sent a sweet wish to his fans on Twitter, writing: "Let's all have a loving #ValentinesDay! Love Paul," alongside a picture of himself posing with a heart-shaped bouquet of red roses.

Stevie Nicks shared the love by tweeting: "May your Valentine's Day be intriguing, loving, and spectacular! Love, love, love always", and Billy Ray Cyrus paid tribute to his wife Tish, calling her "My Appalachian Lady..." and adding: "Still My Valentine after all these years. Peace... love... and happiness always. You deserve it... you are sooooo somebody. I'm proud of you."

Kristin Chenoweth posted a shot of herself with her boyfriend and her dog and captioned the shot: "#ValentinesDay with my two valentines in Nashville I love them!!", and actress Zooey Deschanel celebrated with a photo of herself clutching a bouquet of flowers and captioning the snap: "I love flowers. I love love. Happy Valentine's Day! Hold the ones you love extra tight!"

Alessia Cara was celebrating after a "cute flight attendant" called her "buddy", while Sara Bareilles tweeted: "I love you. Don't forget to love yourself too. Happy Valentine's Day to all the human shaped hearts out there," and Common shared a Toni Morrison quote with his followers: "Love is divine only and difficult always. If you think it is easy you are a fool. If you think it is natural you are blind."