'Let her do her thing': Former SF Mayor Willie Brown reacts to Sen. Kamala Harris' speech with Joe Biden

SAN FRANCISCO (KGO) -- The best thing Democratic nominee Joe Biden can do with his new VP pick? Step out of the way, says former San Francisco Mayor Willie Brown.

Brown is a longtime mentor of Sen. Kamala Harris, who was officially announced as Biden's running mate on the 2020 Democratic ticket Tuesday. Brown and Harris also dated for two years in the '90s.

MORE: Joe Biden, Kamala Harris make first joint appearance as running mates

"Kamala Harris is such an impressive person on the podium," said Brown in an interview with ABC7 News. "Biden should let her do her thing. It would be like someone trying to control Tiger Woods at his zenith."

"There were clear reservations about her candidacy as overshadowing the presidential nominee, in this case Biden," he said. But in their first joint appearance, Brown says, "She demonstrated today she can be a true team member."

RELATED: Everything you don't know about Kamala Harris' San Francisco Bay Area roots

"I give her an A+."

See more from Mayor Willie Brown in the video at the top of this story.