Reese Witherspoon and daughter Ava don't think they look alike: 'We don't see it!'

Reese Witherspoon's 17-year-old daughter, Ava Phillippe, is often hailed as her famous mom's lookalike, but the 40-year-old actress says that they personally have trouble seeing the resemblance.

On Tuesday's episode of The Ellen DeGeneres Show, Witherspoon admitted that "everybody keeps saying" she greatly resembles her oldest child, whose father is Ryan Phillippe. "She and I are always like, 'We don't see it!'" she exclaimed.

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On Monday, Witherspoon excitedly reunited with her Cruel Intentions co-star, Selma Blair, and snapped a selfie. "Happy holidays y'all!!" Blair captioned the photo. "An incredible time with this sunny superstar and all the beautiful kids at a magical @baby2baby and @tinyprints holiday morning with Santa."

See photos of the pair together through the years:

EXCLUSIVE: Ryan Phillippe Opens Up About How He and Ex Reese Witherspoon Co-Parent During the Holidays

In a previous interview with ET, Blair did hint that the two wouldn't be opposed to sharing the screen together again some day. "She's been a friend since Cruel Intentions," the 44-year-old actress gushed. "I would act with her any day."

WATCH: Double Take! Reese Witherspoon and Daughter Ava Phillippe Look Nearly Identical

In the meantime, Witherspoon is busy promoting her latest animated movie, Sing. Earlier this month, she brought along her doppelganger daughter and the rest of family to the film's premiere.

Witherspoon told ET that while Ava and her two brothers, Deacon, 13, and Tennessee, 4, might give their mom a hard time for singing along to Drake, they do give her props for being able to work her own social media accounts.

"Well at least I know how to work Snapchat," she quipped. "I think, you know, most moms don't. [My kids] are like, 'You actually know what Snapchat is and you're actually sending us a lot of Snapchats.' So, maybe that's kind of a cool thing."

WATCH: Reese Witherspoon on Getting Advice From Her Lookalike Daughter -- 'I Depend on Her Brutal Honesty'