Pete Davidson Says Age Difference with Kate Beckinsale NBD, Just Ask Trump

Pete Davidson's taking a shot at haters who think he's too young for Kate Beckinsale -- by calling out dozens of male celebs who date way below their age ... starting with President Trump.

The shots were fired during the Weekend Update segment on 'SNL' ... Pete made it clear he and his new bae hear all the buzz about him being 25 and her being 45 but said they don't let it bother them.

Pete then took a deep breath and said direct your "big age difference" questions to ... Leo DiCaprio, Richard Gere, Jeff Goldblum, Derek Jeter, Michael Douglas -- you get the point.

He rattled off more than 20 names in the one breath ... including POTUS and, yes, even the guy who plays Trump on 'SNL.'

The hilarious defense of Kate comes a week after their Madison Square Garden make-out session.

Pete might not be getting tattoos of Kate just yet, but the fact he's adding her to his 'SNL' routines is a sign the relationship is going strong.