The singer and actress even wore a gold nameplate necklace that reads 'Elyes' in a photo that she shared to express those birthday wishes.
"#HappyBirthday to this guy…@elyes_gabel. Give him some bday [love]," she captioned the photo.
Katharine McPhee was first spotted wearing her boyfriend's name around her neck during a recent vacation in April--helping confirm rumors that she is in fact dating the Scorpion star.
A source recently confirmed to Us Weekly that Katharine McPhee and Elyes Gabel are very much in love.
McPhee has remained very good friends with her ex-husband Nick Cokas as well. The two had breakfast together recently as part of a breakfast meeting.
Katharine McPhee and Nick Cokas divorced following the release of a photo that showed her making out with Smash director Michael Morris. Morris was able to salvage his marriage following the ordeal.
It's uncertain what Katharine McPhee and Elyes Gabel did to celebrate his birthday last week, or if the two were even able to spend the day together. It's clear, however, that Katrharine McPhee has moved on and found new love, and that she is very happy with the Scorpion star.