He responded with a "Thank You" followed by several heart emojis.
The post also included several snaps of Mark with Kelly, their friends and family.
Mutual friends of Kelly and Mark's, like Sarah Michelle Gellar and Priyanka Chopra, also chimed in on his big day.
Kelly and Mark met on the set of All My Children back in 1995. They eloped on May 1, 1996.
They have three children together: Michael, 21, Lola, 17 and Joaquin, 15.