says that with four children, "sleep is non-existent" and some days fatherhood is a roller coaster ride.
"It's the most fun I have ever had and also the biggest pain in the ass I have ever experienced," he told reporters at the Venice Film Festival on Sunday. "(But) I love it and I can't recommend it any more highly."
When asked by Italian state TV if he and partner Angelina Jolie
were ready for a fifth child, Pitt replied: "Yeah, we're ready."
The couple arrived in Venice on Saturday with all four children in tow and headed for the exclusive Hotel Cipriani, on Giudecca island, a short boat ride from Venice.
While Pitt promoted his latest film, The Assassination of Jesse James by the Coward Robert Ford
, which is in competition for the festival's Golden Lion top award, Jolie enjoyed ice cream and a stroll with their 2-year-old daughter Zahara and son, Maddox, 6.
Pitt, 43, who co-produced and stars as Jesse James in the film, said that having a family has also helped his career.
"It makes me much more efficient," he says, "because that's the main focus. It makes me feel when I do have time to work, I really do have to focus because there is a really short window to get something done. I am quite pleased by it all."
On Sunday evening Jolie joined Pitt on the red carpet for the premiere of the film along with co-stars Casey Affleck and Sam Shepard.
Pitt wore a white tuxedo and Jolie wore a black lace gown and more than $2 million worth of Bulgari jewelry. They signed autographs before heading into the screening, arm in arm.