Opposition leader and Yesh Atid chair Yair Lapid announced Major-General (res.) Noam Tibon will join the Yesh Atid party in a statement on Tuesday.
Lapid and Tibon will deliver a joint statement at 7:15 p.m.
Tibon, 63, served for about 34 years in the IDF, including as commander of the Nahal Brigade, the Judea and Samaria Division, the Joint Command and Staff College, and the Northern Corps.
The October 7 massacre
On October 7, Tibon drove to Kibbutz Nahal Oz, where his son Amir and his family live, and, together with a Maglan unit, rescued residents from the kibbutz, including members of his own family.
Hiding in their safe room, Amir texted his father that from about 7:15 a.m., they could hear terrorists shooting and talking just outside their window.
Tibon took his gun and tried to reach his contacts in the IDF while Gali, his wife, speedily drove them towards the Gaza Envelope area.
Along the way, they picked up a couple who had escaped from the Nova music festival and took them to a safe location, then stopped to help soldiers who had been wounded at a roadblock.
Gali took the soldiers to the hospital, while Tibon joined another former IDF general, Israel Ziv, who took him to Nahal Oz.
Since October 7, Tibon has been active in the weekly protests demanding a return to all hostages held in Gaza.
This is a developing story.
Hannah Brown contributed to this report.