"Yes yes yes it will always be yes," Benoist, who portrays the titular character on the CW series said on Sunday alongside a selfie of herself showing off her engagement ring as Wood kisses her cheek.
Wood, who joined the show in 2016 as Supergirl's love interest Mon-El, also posted the same image. "The happiest," he said.
Benoist, 30, and Wood, 30, were first linked together in March 2017 when they were spotted in Vancouver, B.C.
Benoist was previously married to her Glee co-star Blake Jenner. Benoist filed for divorce in Dec. 2016 after they tied the knot in July 2013. The divorce was finalized in December 2017.