John Stamosoffered some brotherly love to hisFull HousecostarDave Coulier.

After Coulier revealed hehas been diagnosedwith Stage 3 non-Hodgkin lymphoma, Stamos took to Instagram to show his support.

Stamos posted a series of photos of the pair, including snaps of them on the set ofFull House.

HOLLYWOOD, CA - AUGUST 19:  John Stamos and Dave Coulier attend Cinespia’s screening of ‘Some Like It Hot’ held at Hollywood Forever on August 19, 2017 in Hollywood, California.  (Photo by Kelly Lee Barrett/Getty Images)

John Stamos and Dave Coulier.Kelly Lee Barrett/Getty Images

My brother from day 1, he wrote in the caption.

Love you @dcoulier and Ill be by your side through it all.

A post shared by John Stamos (@johnstamos)

Coulier shared the news during an interview ontheTodayshowyesterday.

His doctor then ordered a series of tests, which came back normal.

Blood tests came back great.

My EKG, everything great.

Heart, everything perfect, Coulier said.

A few days later, tests revealed that Coulier had B-cell lymphoma.

The first thing I said to them was, Wait a minute cancer?

You always hear about it happening to someone else.

Much of the cast hasremained closesince the series ended in 1995, especially afterSagets suddendeathin 2022.