Sienna Miller says her friend, Keira Knightley, will be a great mother.

The 32-year-old actress shared her thoughts to Page Six at the premiere of her new film, American Sniper.

Knightley, 29, and husband James Righton, who were married in May 2013, revealed they are expecting their first child earlier this week.

“We’ve spoken a lot and I know she will be amazing,” Miller told the newspaper. “She doesn’t need any advice. She will be perfect.”

Miller knows a bit about what it takes to be a great mom. She and boyfriend, Klaxons star Tom Sturridge, welcomed their own beautiful daughter, Marlowe Ottoline, in July 2012.

What Sienna Miller said about Keira Knightley's baby news was just lovely: http://t.co/uNSVFDg4UU pic.twitter.com/kse6C9hcCv

— Glamour Magazine UK (@GlamourMagUK) December 18, 2014

Keira Knightley is pregnant! She and husband James Righton are expecting their first child http://t.co/NIH4fNEJuK pic.twitter.com/rrzxNmjdpj

— People magazine (@peoplemag) December 12, 2014

In the January edition of Vogue, Miller said she couldn’t imagine life without her little girl.

“I was overwhelmed by how normal it felt,” she said. “It was like, ‘There you are — that’s what I’ve been missing.’ Like we’re both in on something only we know. An amazing sense of being complicit with a little being.”

Sienna Miller on the joys of motherhood and her Twitter fears http://t.co/ikyAxh1BfE pic.twitter.com/ZfzOW2QF1a

— Stylist Magazine (@StylistMagazine) December 17, 2014

ICYMI: Congratulations to Keira Knightley who has confirmed her pregnancy http://t.co/vp0FaQLLZf pic.twitter.com/V5gaxCORa3

— HELLO! (@hellomag) December 12, 2014

Miller currently stars with Bradley Cooper in American Sniper, and will next appear in Mississippi Grind with Ryan Reynolds.

Knightley will portray Jan Hall in Everest in 2015.