Neil Patrick Harris is set to marry his boyfriend David Burtka.

The actor, who plays party-loving Barney Stinson on the hit comedy How I Met Your Mother, announced via Twitter that the pair would be tying the knot after New York's state senate voted to legalise same-sex marriage.

"It PASSED! Marriage equality in NY!! Yes!! Progress!! Thank you everyone who worked so hard on this!! A historic night," he wrote.

"David and I did propose to each other, but over five years ago! We've been wearing engagement rings for ages, waiting for an available date."

Neil - who also made an Emmy-winning performance on Glee as former Glee Club star Bryan Ryan - has been dating David since 2004.

The pair are fathers to twin boy and girl Gideon and Harper, born by surrogate in October last year.

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