Tessa Thompson, who played the role of Valkyrie in Thor: Ragnarok last year, has reportedly joined the Avengers 4 reshoots. The latest development also tallies with what many have suspected for a long time.
That Valkyrie did not die when Thanos’ spaceship attacked Thor and the Asgardian spaceship at the end of Thor: Ragnarok. Half of Asgardians were massacred by Thanos and his Black Order, but the other half were either allowed to go or escaped themselves.
Thor himself revealed this while talking to Rocket when the two along with Groot were on the way to Nidavellir (to get a new weapon forged for Thor).
He said Thanos killed half of his people but did not say where was the other half. One of the directors of Avengers: Infinity War and Avengers 4, Joe Russo has said that Valkyrie will be back. But this is our first confirmation that she will be a part of Avengers 4.