The pop star mentioned his death on Monday, tweeting: "I lost you to the summer wind."
She then traveled to New York City on Wednesday to appear on "Good Morning America" but will still mourning the death of "grandps," who taught her to "always be professional."
She tweeted: "only reason I made this twelve hour trip is grandps told me he wanted me to always be professional & fulfill my business commitments :("
She also wore a loose fitting outfit while visiting "Jimmy Kimmel Live" on Monday.
A source told Usmagazine.com: "Zoe is about three months pregnant. But she will only announce the news when she's ready."
Saldana, 36, married Italian artist Marco Perego last year.
Another insider told the magazine, "Zoe has always wanted a big family.....