For over two decades the 74-year-old actress has been pals with Keanu - who she first met when he starred in her husband Taylor Hackford's 1997 supernatural thriller 'The Devil's Advocate' - and she is fully behind his relationship with Alexandra Grant, who he made his red carpet debut with at the LACMA Art + Film Gala this week.
Speaking to 'Entertainment Tonight', Helen said: "I do know Keanu very well. He did a film with my husband and he is just the most adorable, lovely person. So she's a lucky girl and I'm sure that he's a lucky boy."
Alexandra, 46, first collaborated with Keanu, 55, in 2011 on his book 'Ode to Happiness', with the artist providing the illustrations, and reunited again to work on his 2016 book 'Shadows'. From there, romance blossomed between the pair.
The 'John Wick' star - whose daughter Ava was tragically stillborn in December 1999, just a month before his girlfriend Jennifer Syme died in a car accident - hadn't been publicly seen with a partner for years, before the pair were photographed enjoying dinner together at Giorgio Baldi, a luxurious Italian hot spot, in Santa Monica, California, last month.
Keanu has reportedly decided to go public with his new love interest because he's "extremely happy" with her.
An insider told People magazine: "Keanu wants to openly share his life with her. He is extremely happy and grateful to have Alex in his life. [They] started dating earlier this year, but have wanted to keep it quiet."
Helen also admits she was extremely "flattered" when fans mistook Alexandra - who wore her natural, silver hair tied back in a bun with her bangs down - for 'The Good Liar' star.
When asked about the case of mistaken identity that took Twitter by storm, Helen said: "I saw that. That was very flattering on me, you know, because she's obviously lovely."