Carrie's bro tells TMZ ... "It's heartbreaking and shocking to me that I was intentionally omitted from attending this important legacy event for my sister, Carrie."

Todd, the son of late singer Eddie Fisher and late actress Debbie Reynolds, says the snub is ironic because he claims he's the one who got the ball rolling on getting Carrie a star on the Walk of Fame ... and he says he's worked tirelessly to honor and preserve the family's Hollywood legacy.

Todd says he and Carrie were inseparable for more than 60 years -- so, he views the guest list snub as "extremely hurtful and distressing as I was always a big part of everything my sister and mother did historically over their lifetimes."

Todd points out he went with Carrie to their mother's own Hollywood Walk of Fame ceremony back in the day, as well as her handprint dedication at the famed Chinese Theatre. Fittingly, Carrie's getting her star Thursday, May the 4th (be with you) ... aka "Star Wars Day."

When Todd found out he didn't make the guest list cut, he says he had his team reach out to the Hollywood Chamber of Commerce, which oversees the Walk of Fame plaques, for clarity ... and he says he was told the guest list was controlled by Disney.

Todd says Disney told him the final say came down to Carrie's family ... and he says he was told they had filled the 30 seats they were given and to not add anymore stress to his niece, Billie Lourd, over his snub.

Carrie's brother says the event is about her -- not him or his family -- but adds, "Frankly, it's a distressing situation and I don't deserve to be put in this position. As the only brother of the Carrie Fisher, being omitted from this special day is truly hurtful."