Fabregas and Pique came through Barca's youth academy together before heading to Arsenal and Manchester United respectively and the pair are now key members of the hugely successful Barca and Spain squads.
An avid user of Twitter to showcase his quirky sense of humour, Pique has a reputation as the clown in the dressing room and he was up to his usual tricks when he ran around the pitch at a Euro 2012 training session with only one boot on.
Fabregas joked in El Pais daily on Wednesday that it had taken time to get used to him again.
"It's one of the things you have to adapt to," the paper quoted him as saying. "It's not easy, it's been tough."
Fabregas has been under the microscope even more than usual at Euro 2012 since Spain coach Vicente del Bosque opted to deploy him as a roving forward in Sunday's Group C opener against Italy and started without a recognised striker.
The 25-year-old netted Spain's equaliser in a 1-1 comeback draw and it remains to be seen whether Del Bosque uses the same tactic for Thursday's match against Ireland.
On a more serious note, Fabregas told El Pais that people were wrong to think returning to his boyhood club had been easy.
He started his first season back at Barca with a bang but his form tailed off towards the end of the campaign and Pep Guardiola left him out of several key matches.
After shaking off a hamstring strain sustained just before Euro 2012, he has looked sharp and hungry in training and his goal against Italy came after a trademark surging run into the penalty area.
"It has been a radical change in my life and like it or not it is hard to adapt," he said.
"I went from playing with complete freedom of movement to Barcelona where the game is more positional," he added.
"It was a challenge and I went through a period where I was very worried about it."
Spain take on Ireland in Gdansk on Thursday after Italy meet group leaders Croatia, who beat Ireland 3-1 on Sunday.