https://www.cnbc.com/2019/01/04/house-speaker-pelosi-invites-trump-to-deliver-state-of-union-address-on-jan-29.html
"In the spirit of our Constitution, I invite you to deliver your State of the Union address before a Joint Session of Congress on Tuesday, January 29, 2019 in the House Chamber," Pelosi said in the letter. "I look forward to welcoming you to the Congress."
haven't been able to find a copy of the whole letter