The Hollywood action superstar with a resume including blockbuster film franchises Jurassic World, Avengers and Guardians of the Galaxy doesn't have short legs.

He stands at 188cm and has muscles bulging out of his long-sleeved T-shirt.

Pratt's problem is the couch he's sitting on.

"I'll tell you the problem with this couch, OK?" Pratt said as he continued his rant.

"It's designed for an NBA player.

"No one's femurs are as long as this."

Pratt, as he is known to do, is joking around.

The white leather couch he has declared war on appears as though it should be on display in an art gallery.

Its odd proportions include a long cushion to sit on and short backrest.

"I have to be Kareem Abdul-Jabbar to sit on this couch comfortably," said Pratt, referring to the 218cm basketball great.

Pratt's jokes about the couch were performed in front of a large group of journalists at the SLS Hotel in West Hollywood to promote his new Disney-Pixar animated family film, Onward.

His co-star and fellow Avenger Tom Holland has the same chair but isn't complaining.

Ditto for Onward director Dan Scanlon and producer Kori Rae.

"I'm mostly concerned because, you know, there's a bunch of cameras," Pratt, stretched back on the couch and with his chin on his chest revealing an unflattering look, continued.

"It's a terrible angle."

Onward took six years to make and was inspired by Scanlon's relationship - or lack of a relationship - with his father, who died when Scanlon was just one year old.

Scanlon's brother was three years old.

Onward tells the story of two brothers who through magic manage to bring their late father back to life, although there is a catch.

They only bring half of their dad back - from the waist down - and are in a race against time to make the top half materialise.

"What if you could meet him?" said Scanlon, posing the questions that led him to make the film.

"If you could have one day what would you ask him?"

Pratt, 40, and Holland, 23, voice the two brothers.

The actors had developed a brotherly relationship on the Avengers set so there was plenty of chemistry when they stepped in the Onward sound booths.

"It was almost like we were just playing ourselves," Holland said.

Pratt voices big brother Barley and Holland younger brother Ian, a reversal for Pratt's life growing up in Minnesota, where he was the annoying youngest sibling.

He idolised his older brother Cully, who went on to join the army.

In high school, Pratt would wear the clothes his brother wore the previous day.

"I'd pick them up off of his floor and put his clothes on because he had nice-smelling cologne, he had style and knew how to match his clothes," Pratt recalled.

"His friends started to notice and he kindly said, 'Hey, man, I think you need to stop wearing my clothes the day after me because my friends are noticing that'."

Pratt now realises how annoying it must have been for Cully.

Almost as annoying as the white couch he's faced with in West Hollywood.

"This is built for somebody who has a room that no one will ever sit in," said Pratt, firing off another complaint.

"This is a couch for a very rich person because as soon as someone sits in this couch, it would be like, 'Let's take this back!' "

Onward opens in Australian cinemas on March 26, with advance screenings beginning March 20.

Australian Associated Press