Robert Downey Jr. has ''missed'' his son ''a lot'' while promoting 'Avengers Assemble'.
The 47-year-old actor - who already has son Indio, 18, with ex-wife Deborah Falconer - and his spouse Susan Levin welcomed baby Exton Elias into the world two months ago, and he loves being around his ''really cute'' little one, but wishes he could have spent more time with him since his birth.