Dave Grohl's bad mood at Wimbledon now makes sense ... the rocker stepped out with his wife, Jordyn Blum, at the tournament weeks before confessing he's fathered a baby outside his marriage.
Check it out ... the Foo Fighters frontman had a blatantly snippy attitude while being interviewed at the London tennis event back in July.
In the footage, a BBC Sport reporter politely asked Grohl for any final predictions for the tournament at the All England Lawn Tennis and Croquet Club ... but the rock legend offered up only short, bland retorts.
He eventually just walked away from the reporter ... leaving fans confused about his unnecessarily blunt behavior.
In fact, when the video was first posted, one fan claimed Grohl had been "acting slightly pissy recently."
Following the Nirvana alum's confession that he welcomed a baby daughter outside his marriage to Blum ... many have speculated this was the root cause of his brusque demeanor in Britain.
Some even joked this drama had Grohl worrying about a possible divorce!!!
As TMZ previously reported ... Grohl confirmed the baby bombshell on Instagram Tuesday, where he told his fans he planned to be a supportive father to the child ... while also making attempts to regain the trust of his wife and children.
Grohl and Blum, who have been married since 2003, share 3 daughters together ... Violet Maye, Harper Willow and Ophelia Saint.
Here's hoping Grohl is a bit nicer now that he has this weight off his chest!!!