Sharon & Kelly Osbourne Reveal What Makes Them 'Best Friends'

Sharon Osbourne and daughter Kelly have forged as close a bond as any mother and daughter, as we saw on our ET stage.

Sharon Osbourne and her daughter Kelly have forged a close bond as mother and daughter, and the two visited the ET stage for a mini lovefest ahead of Mother's Day.

"My mom gave up so much for me and my brother," Kelly gushed. "I can't even put that into words."

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Sharon was 32 when she had Kelly in 1984 and gave birth to Jack the following year. The Talk co-host raised her little tykes with husband Ozzy all while juggling her career.

"I wouldn't have anything without you guys," Sharon said. "When you think about it, I gave up nothing. It was hard because I was working, but I say to all mothers who can just be there full-time for their children, it's a blessing. It's the greatest gift anyone could ever have."

Likewise, Sharon has given Kelly many intangible gifts in the form of motherly advice. Kelly joked that it can sometimes "drive her nuts" how right Sharon can be about everything.

"It comes with the years -- that's all," Sharon said. "I've been around a long time."

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In the book A Letter to My Mom, Kelly pens a tribute to Sharon alongside letters from Kristin Chenoweth, Shania Twain and that were written to their respective mothers.

"I couldn't be me without you, and that's the truth," Kelly said.

Sharon gave Kelly a special gift on the ET stage when she made an admission that Kelly has been waiting to hear for years.

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"I think the hardest thing I have with Kelly is to let her be her," Sharon said.

"Thank you for saying that," Kelly said. "She's never said that out loud before. Best day ever!"