Jada Pinkett Smith is shedding light on a special friendship with Tom Cruise in her new book.

The memoir Worthy, which chronicles Pinkett Smith’s journey from Baltimore to Hollywood and beyond, includes a revealing story about the Mission: Impossible star — and his dirt bikes.

“Early in our friendship, Tom and I found out we shared a love of motorcycles, and I was super excited when we made a plan to ride on his dirt-bike track,” the actress, 52, writes. “Enjoying the ride, I had no qualms about trying to jump off a small ramp, only to feel the thrill of catching air. The problem was that after going up, the bike and I descended rapidly to the ground, and I couldn’t manage to land the bike.”

“As soon as I hit the ground, I was thrown from the bike and landed on my back, hitting my head hard. Thank God I had on a helmet.”

The Set It Off star says Cruise, 61, rushed to her side to make sure she was okay: “Relieved but concerned, Tom let me know I’d done some good riding but that I should stop for the day.”

“Bringing myself to my elbows, I looked up at him and asked a really important question of him and of myself: ‘How many times have you reminded me to not let fear stand in my way? If I don’t get back on this bike right now and do another lap, I may never get on a bike again.’”

Cruise then “smiled the biggest smile,” she writes, and told her, “‘Okay, one more round.’”

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Pinkett Smith starred alongside Cruise and Jamie Foxx in the Oscar-nominated 2004 hit movie Collateral, directed by Michael Mann.

In Worthy, she shares more details about the friendship with the Top Gun actor that began then — and why she needed that encouragement to try another go-round on his track.

“I was scared as hell to get back on that bike,” she writes, “but the lesson was — it’s not about NOT being scared when you need to move past fear. It’s about finding the courage to freaking do it anyway, even if you don’t think you can.”

Pinkett Smith continues: “Finding the courage is easier when someone has confidence in you — like Tom with me getting back on the bike.”

Cruise, she says, had the ability to see through what she calls “my great act of having it all together all the time. Without saying it, he picked up on moments when I was feeling far less than worthy.”

When doing press or premiere appearances together, she remembers, Cruise would “look me right in the eye [and say], ‘never forget how smart and talented you are. Now go out there and make somebody smile because you shook their hand on the red carpet today.”

“That was so helpful. All I had to do was get past my fear.”

In the same chapter, titled “Wild Banshee,” Pinkett Smith details how her husband of 25 years Will Smith similarly encouraged her not to drop out of touring with her rock band, Wicked Wisdom, upon receiving medical advice to do so.

She writes that her memory of dirt biking with Cruise “amplified the idea that it wasn’t about trying to prove something to other people, but about proving to myself that I could finish what I started.”

Her memoir isn’t the first time Pinkett Smith has expressed gratitude for her friendship with Cruise. “I used to believe I wasn’t pretty, because growing up, I was never told that I was,” she said in a 2011 interview with Redbook magazine. “It was Tom Cruise who taught me how to get rid of those doubts.”

“He said, ‘Every time I compliment you, you always reject it. You need to stop doing that. Just say, “Thank you.”’ So I’ve learned to accept a compliment.”

Worthy is now available wherever books are sold.