Presumptive Democratic nominee Joe Biden says former President Barack Obama told him that when picking a vice presidential running mate, he should find the yin to his yang.

Speaking to donors during a virtual fundraiser Wednesday, the former vice president recalled the conversation after being asked by a supporter about his own VP pick.

Biden told virtual attendees that he reached out to Obama for advice on picking a running mate, and was told to look for someone who has experience in areas where he is lacking.

Obama reminded him of how that dynamic worked so well between the two of them, Biden said.

“And so I’m going to need a woman vice president who has the capacity, has strengths where I have weaknesses,” he told fundraiser guests.

Biden has previously admitted to speaking with Obama about potential VP choices, telling supporters at another fundraiser in late March that the two discussed the importance of that person being prepared to be president if something were to happen to him.

“They have to be prepared,” he said. “Once I pick someone, God willing, if I’m the nominee, that there’s not going to be any snafu.”

The ex-VP has publicly pledged to select a woman as his running mate, and has teased names such as Gov. Gretchen Whitmer of Michigan, Sen. Kamala Harris of California, Atlanta Mayor Keisha Lance Bottoms and Rep. Val Demings of Florida.