Rob Kardashian is back on Twitter with a cure for Kim's morning sickness

Los Angeles - Rob Kardashian has returned to Twitter to give Kim Kardashian West the cure for morning sickness.

The 28-year-old reality TV star - who has been battling weight gain and depression for months - hadn't posted on the social media website since 29 May but came back to his account on Tuesday.

He returned to Twitter to give his 34-year-old sister - who is pregnant with her second child with husband Kanye West - some advice for the nausea she's been experiencing.

When Kim tweeted that she "thought this nausea thing was supposed to be gone by now", Rob replied: "I sent u that voice note. It should help."

@KimKardashian I sent u that voice note. It should help

— ROBERT KARDASHIAN (@robkardashian) June 23, 2015

The Keeping Up With The Kardashians star then replied: "Should I post it? I think people would love to hear the voice notes u send me! (sic)".

While it's unclear what the voice note included, Rob later referenced Khloe Kardashian's ex French Montana's lyrics from Hard Work.

@KimKardashian HARD WORK GONE PAY OFF?? I BE HIGH OFF THIS MONEY I DUNNO WHAT THEY BE ON??

— ROBERT KARDASHIAN (@robkardashian) June 23, 2015

Rob's last tweet to his older sister - who is due to give birth to a son later this year - compared her to that "bitch from Gone Girl", so the siblings have obviously made up.

A source close to the Kardashian family previously said: "He has a funny sense of humor and posts weird things and then deletes them. It's just him."