Underwood posted the pics alongside a touching message for the NHL star, commemorating their long, lasting love.
"Here’s to 8 years, babe! Where does the time go?!" she wrote. "I love you today more than yesterday...which was more than the day before...and so on and so forth."
"Here’s to many more years together!" she added. "[Heart] you."
The happy couple -- who began dating in 2008 after meeting at one of Underwood's concert performances -- tied the knot in 2010 during a lavish ceremony at The Ritz-Carlton Lodge in Greensboro, Georgia.